Realistic Rendering Of 3D Terrain Scenes Based On Fractal Theory

Virtual Reality has been widely used in the fields such as computer simulation, digital earth, game and entertainment, etc. These application need not only realism complex Virtual Environment, but require the user can interact with the virtual scene at interaction frame rate. As long as meeting the real-time rendering, the user can feel the virtual environment is the same as the real world and immerse into the environment. However, Virtual reality communities and other visualizations have always faced the problem that their "desirable" visualization dataset sizes are one or more orders of magnitude larger than what the hardware can display at interactive rates. Thus Realistic rendering of 3D terrain scenes is a challenging subject. It has two aims,which are reality of rendering and real-time of rendering.It should maintain higher interactive frame rates without noticeably degrading image quality.Fractal theory was used to generate 3D terrain scenes in this paper.For the purpose of real-time,continuous LOD algorithms and other techniques were used to accelerate terrain rendering.For the purpose of reality,texturemapping and lightmapping was used.Realistic rendering of 3D terrain scenes based on fractal theory was generated in normal PC.The reality and real-time was enough. This thesis focuses on the theoretical and methodological studies in the several subtopics: 3D terrain rendering, fractal terrain simulation, terrain simplification and multiresolution terrain representation.These studies are based on some interdisplines such as 3D computer graphics, computer geometry,scientific computation visualization and virtual reality, The goal of this thesis is to build a technological framework for visualization and real-time rendering of 3D terrain surface. The main results of this study are summarized as follows. (1) Based on OpenGL library and its work principle, the process of 3D surface rendering is analyzed at length. Some methods are presented to improve rendering effects and to speed up graphic display. The voxel-based terrain rendering technique is also discussed. (2) On the basis of fractal theory, the terrain simulation is systematically studied and carried out using fractal Brown motion (FBM) method. For the fractal terrain simulation, the "diamond-square" algorithm based on random midpoint displacement (RMD) is given in detail. (3) Data structures and technical properties of some types of multiresolution terrain representation methods are compared and elaborated. The optimization suggestion is given for the real-time optimally adapting (4) The 3D terrain visualization based on fractal theory and the adaptive quadtree model was applied to the virtual reality of driving simulator. Texturemapping and lightmapping was used.Realistic rendering of 3D terrain scenes based on fractal theory was generated in normal PC.The reality and real-time was enough.