大规模地形实时绘制中的地平线遮挡剔除算法

Horizon occlusion culling algorithm for real-time rendering of large-scale terrain

大规模地形场景包含大量的几何数据,无法一次性载入内存,并具有极高的复杂度,因而无法进行实时绘制。本文提出一种用于大规模地形场景的实时地平线遮挡剔除算法。该算法采用四叉树结构构造地形的多分辨率层次细节模型,按照大致由前向后的顺序遍历地形时构建遮挡地平线,应用地形包围盒技术,把地形区域与地平线相比较,以确定何时它们对于视点来说完全被遮挡并剔除这些被遮挡的区域。实验结果表明在贴地漫游的情况下,显著提高了场景绘制速度,证明了此算法的有效性。

Large-scale terrain scene contains many geometric data,which can not be wholly loaded into the internal memory,and has a very high complexity,therefore can not be real-time rendered.This paper presented a horizon occlusion culling algorithm for realtime rendering of large-scale terrain.The algorithm used quadtree structure to establish the multi-resolution model of terrain.The occlusion horizon was constructed as the terrain was traversed in an approximate front to back ordering.Regions of the terrain were compared with the horizon to determine when they are completely occluded from the viewpoint by using terrain bounding box,and culled away these regions.The experimental results demonstrated that the algorithm improved the rendering frame rate significantly when navigating at ground level,and proved the validation of this algorithm.