基于九宫格的累进LOD地形绘制算法

Progressive LOD Terrain Rendering Algorithm Based on Nine Palaces

为减少地形绘制中地形分割与视点中心块分割的次数,提高绘制效率,提出了九宫格地形快速绘制算法.利用九宫格的特性建立地面多分辨率"块"结构,将每次分辨率变换都集中在周围8格中,使地形分割与视点中心块分割合并为1次;九宫格分层结构使多分辨率模型中模型细节的处理和绘制三角形的个数以17/81的倍率递减,提高了运算速度.提出了边界裂缝消除算法,以修正多分辨率模型产生的裂缝,并对九宫格算法进行了性能分析和误差评估.实验结果表明,当分层数为3时,该算法在保持视觉效果的同时,比四叉树算法的绘制效率提高约14.7倍.

In order to decrease the times of dividing terrain and viewpoint center squared in terrain rendering and improve rendering efficiency,a fast nine palaces terrain rendering algorithm was put forward.In this algorithm,a multiresolution ground block structure is set up based on the characteristic of nine palaces,and level switching of resolution occurs in 8 surrounding squares in the nine palaces.As a result,the operations of dividing terrain and viewpoint center squared are combined to one,and the number of triangles to be processed and rendered declines at the rate of 17/81 to improve the process rate greatly.An algorithm of avoiding cranny was put forward in order to revise the cranny bought by the multiresolution model.The performance analysis and error estimation for the algorithm were carried out.The experimental results indicate that under the condition of holding the visual effect,the rendering efficiency of this algorithm is about 14.7 times that of the quadtree algorithm when level number is 3.