Study On Real-Time Terrain Rendering

In this thesis, we describe the approachs of real-time rendering terrain scenes. We compare the regular grid terrain LOD methods and triangulated irregular network LOD methods, discuss the use of view frustum cull and occlusion cull, analysis the efficiency of different data layou, and take environment influences into account. We cut the large terrain into many small tiles, render these tiles independently. Terrain LOD can be divided into two main classes: regular grids based and triangulated irregular networks(TIN) based. TIN method generates irregular triangle meshes in good shape and needing far less redundant vertices. Especially, for the View Independent Progressive Meshes(VIPM) algorithm, we not only can find very hardware friendly implementations, but also uniform the processing of terrain and models, but VIPM is difficult to sew the seams between the VIPM chunks. Regular grid based methods are inborn for quadtree or binary tree based hierarchies, can efficiently eliminate seams, also can find hardware friendly implementations. In terrain rendering, regular grid based methods is more suitable than TINs. When considering large terrain, we can reorganize input data into cache friendly manner and apply occlusion cull to terrain rendering. We also discuss the implements of texure and light in terrain rendering to achieve photorealism effect. At last, we use above methods to construct a high quanhity terrain rendering system, and give some future research directions.