一种视点相关的大规模地形快速实时生成算法 *

为了解决大规模地形实时漫游过程中,由于不同细节层次模型之间过渡而引起的图像跳变以及图像绘制帧率不高的问题,提出了自底向上的一次性整体构网,网格节点实时更新的建模策略。运用基于块和三角形面片的混合裁剪模式 ,结合简化的高度差投影计算方法,快速选取适合的地形节点 ;然后采用加点、删点、局部更新三种途径对 Delaunay地形三角网进行实时更新。同时在地形漫游过程中实现了对高度差投影限的自适应控制。仿真实验表明,该算法有效地避免了图像跳变现象,与同类算法相比 ,具有较高的图像绘制帧率,特别适合大规模地形的近距离

View-dependent real-time rendering algorithm for large-scale terrain

During the flyover of large-scale terrain, in order to eliminate the popping effect of switching among levels of detail and to increase the frame rates with high image quality, this paper put forward a new bottom-up modeling strategy, which con-structed simplified terrain triangle mesh globally and updated mesh nodes dynamically. Employed hybrid culling technique based on blocks and triangle faces and simplified computing method for screen-space errors to select appropriate terrain nodes rapidly. Then updated the Delaunay terrain mesh by adding nodes, deleting nodes and modifying locally. At the same time achieved self-adaptive control for screen-space error tolerance during the terrain flyover. Results of simulation experiments demonstrate that the algorithm eliminate popping effect effectively, and has a higher frame rate compared with other algo-rithms. So it is particularly suitable for close-distance flyover simulation of large-scale terrain.