Research On Rapid Rendering Technique Of Large Scale Terrain Based On GPU

With the development of satellite and remote sensing technology, the resolution of terrain data become higher, resulting in the scale of the terrain data become larger and larger. The storage, transfer, attempering and management of the mass data brings problems to real time rendering, and the terrain rendering based on CPU can no longer meet the applicational requirement.In order to solve these problems, this paper presents a new technique based on GPU for large scale terrain fast rendering. First, it researches the mechanism of texture images' attempering and rendering, and the mechanism of 3D grid modes constructing. Shifts some of the computation from CPU to GPU, and make the most of GPU, a powerful calculating tool. In the aspect texture images, it presents a mechanics of large scale terrain texture attempering and rendering based on GPU. On the foundation of analyzing the advantages and disadvantages of GPU parallel computing, this paper puts forward an image compression algorithm which is based on Discrete Wavelet Transform (DWT) and Vector Quantization (VQ), and realizes the decompression through GPU programming. This is the kernel of large scale terrain texture attempering and rendering mechamism. The experiments show that the mechamism can improve the real-time rendering effects effectively.In constructing 3D grid model, the main problem concentrates on the simplification of DEM data. First, a simplification method and a multi-resolution representation method which are both based on DWT are put forward. Then, by directly programming through GPU realize DWT and IDWT. Experiments prove that, GPU has obvious advantage to CPU, hence guarantees the simplification method of DEM data based on DWT.In the end, Large-Scale Terrain Rendering system (LSTR) is set up, which is based on GPU. Two experiments are accomplished. The outcomes prove that large scale terrain attempering and rendering technique based on GPU can accelerate the speed of rendering, with good effects.