Large-scale Terrain Rendering Using Hardware Tessellation

Terrain visualization has a wide range of application in computer graphics,geographic information systems, etc. In recent years, the rendering ability of graphicshardware is getting stronger, but it is still difficult to satisfy people for large scale terrainnavigation in real-time. In2010, OpenGL4.0and DX11series hardware launch, makingterrain rendering algorithm available with adaptive triangulation performed entirely on theGPU via tessellation unit. Based on this background, using the recent hardwarecharacteristics, this paper made the research on the following respects.First of all, aim at solving the low speed problem of traditional terrain renderingalgorithm which the adaptive triangulation was usually constructed real-time by the CPUor in preprocessing stage, present a GPU-Geometrical MipMapping terrain renderingalgorithm, with adaptive triangulation performed entirely on the GPU via tessellation unit.Using new OpenGL4.0and DX11series hardware characteristics, the algorithmconstructed the triangulation in GPU, and in the algorithm adopt a new crack-avoidingmethod which guarantees seamless patch triangulation.Secondly, aim at solving the problem that the calculation of detail level of terrainblock cannot precisely show block detail in specified conditions in the algorithm ofGPU-Chunked LOD presented by Egor Yusov, this paper puts forward a way whichcalculate the detail level of inside and the four edges separately, making the detail level ofblock more in line with the local terrain surface feathers.Thirdly, aim at solving the problem of vertex Popping when viewpoint is changingquickly, this paper presents a way which insert interlayer between detail levels of block inlinear interpolation way, making the change of vertex height smoother, avoid the Poppingproblem and increase the rendering speed.Finally, design and implement the algorithm.