利用3D_DP和Quad_TIN的地形实时动态显示算法研究
Real-Time Dynamic Rendering Algorithm of Terrain Using 3D_DP Method and Quad_TIN Model
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摘要: 将地貌综合的三维Douglas-Peucker方法引入到地形LOD中,通过构建Quad_TIN模型,提出了一种地形实时动态显示的新算法。该算法首先从全局重要性角度将不规则采样点分级;再利用孤立分割的方式建立四叉树空间索引,结合了规则格网的四叉树结构和不规则采样点的TIN结构在虚拟表达中的优势,并消除了节点间的依赖关系;然后,根据视距和模拟误差确定四叉树的绘制层次和插入采样点的顺序及数量;最后,通过添加拆分点消除节点间裂隙。实验表明,该算法在保证地形表达速度的同时提高了模拟精度,对其他模型的LOD表达也是一种借鉴。Abstract: Through introducing the three-dimensional Douglas-Peucker method for the geomorphology generalization to Level of Details of terrain and building the Quad_TIN model,we put forward a new algorithm for the geomorphic real-time dynamic rendering.The strategy of this algorithm is to classify the irregular sampling points from the perspective of the global importance firstly.Then the structural advantages of quadtree of GRID and TIN of the sampling points are combined in terms of visual expression and the dependence is removed by constructing quadtree spatial index in manner of isolated partition.After that,according to the viewing distance and simulation error,the divided level of quadtree and the inserted order and number of sampling points are quickly determined.Finally,gaps between nodes are eliminated through adding splitting-points.Experiments have proved that the simulated accuracy can be improved greatly with satisfactory speed.
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