多分辨率地形模型动态构建与实时显示研究

Study on Dynamic Constructing and Real-time Rendering of the Multiresolution Terrain Model

论述了一种基于大规模格网数据或离散高程点动态构建多分辨率地形模型的算法。基于三维透视投影理论,实时计算视野区域,在该区域内,通过地形的自身复杂程度、视点位置及视线与局部地形的方向关系确定三角形的六叉分割,构建地形层次三角网(HTIN),并利用包含三叉树子节点的四叉树管理HTIN,优化了HTIN的形状,提高了算法的效率。实验结果表明:该算法在三维地形的逼真显示与实时交互绘制方面均取得了较好的效果。

This paper presents a dynamic construction algorithm for the multi-resolution terrain model based on the large scale GRID data or discrete elevation data. We calculate the field of vision following the theory of three dimensional perspective projections. In the field of vision, the hierarchical triangulated irregular network (HTIN) is constructed through hexa-splitting of triangle, which is determined with three criterion: the complexity of terrain, the position of view point and the orientation relation between terrain tile and the line of sight. The HTIN is organized by quad-tree which includes trinary tree node. This algorithm optimizes the shape of HTIN and improves the efficiency of constructing. The experiment results show that this algorithm can achieve good performance both on the quality of landscape and on the speed of the rendering.