面向大规模地形的瓦片调度与实时绘制算法  

Dynamic Scheduling and Real-time Rendering Method for Large-Scale Terrain

作　　者：刘浩[1,2,3] 曹巍[4] 赵文吉[1,2,3] 宁方馨[1,2,3] 潘李亮 

机构地区：[1]首都师范大学资源环境与旅游学院,北京100048 [2]北京市城市环境过程与数字模拟重点实验室-省部共建国家重点实验室培育基地,北京100048 [3]三维信息获取与应用教育部重点实验室,北京100048 [4]中国科学院地理科学与资源研究所,北京100101 [5]北京合歌科技有限公司,北京100085

出　　处：《计算机科学》2013年第06A期120-124,共5页Computer Science

基　　金：国家自然科学基金项目(41001300)资助

摘　　要：随着图形硬件性能的提升,大规模地形绘制的主要瓶颈已从绘制能力不足转变为大数据的传输,针对这一问题提出一种支持大规模地形的瓦片调度与实时绘制算法。将超大地形数据以瓦片金字塔形式存储于硬盘,绘制每一帧时只调度当前场景所需的少量瓦片进入显存。首先利用GPU实时计算地形网格点的地理坐标并传回CPU分析可见范围,然后采取瓦片四叉剖分、规则化处理和瓦片合并等一系列操作在所有LOD层中拣选最优瓦片集合并调入内存,在内存中利用一块固定大小的缓存进行管理与更新,并最终以单张纹理的形式传入显存进行采样和绘制。实验表明,该算法节约了大量的显存带宽,有效提升了系统在数据传输方面的执行效率,在大规模地形调度与绘制中取得了较好的效果。Along with the development of the graphics hardware, the transmission of large-scale data has replaced the lack of rendering capacity as the new bottleneck of large scale terrain rendering. Aiming at this problem, we present a new approach for dynamic scheduling and real-time rendering for large-scale terrain. Terrain data are stored as tile-pyramid in hard disk, in real-time rendering phase, only a few of tiles are streamed into the video memory every frame. First, GPU computes and transfers geographic coordinates of the current scene into CPU in real time,CPU analyses and calcu- lates the visible region through these coordinates, and then selects the optimum combination of visible tiles（visible tiles set） among all the layers by quad-tree generating, tiles regularization and tiles merging. The visible tiles set are streamed into CPU, managed and updated in a fix-sized buffer, and finally transferred into GPU as a texture for sampling and rendering. Experiments show that this algorithm saves a large amount of video memory bandwidth, improves the efficiency of data transmission effectively,and obtaines a good result in the large scale terrain scheduling and rendering.

关 键 词：大规模地形绘制 动态调度 VIRTUAL TEXTURE 瓦片选取 瓦片管理 GPU 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]