三维场景地面坐标拾取的射线投影算法  

The Algorithm of Ground Coordinates Picking in 3D Scene Based on Projection of Ray

作　　者：李奇峰[1] 郭同德[1] 

机构地区：[1]郑州大学水利与环境学院,河南郑州450001

出　　处：《测绘科学技术学报》2014年第1期93-96,共4页Journal of Geomatics Science and Technology

摘　　要：简述了虚拟三维场景中对象拾取及地面坐标拾取的基本原理,分析了实时地面坐标拾取的研究背景和现状;提出了基于射线投影的地面坐标拾取算法。该算法利用射线在水平面的投影确定可能与之相交的三角形集合,从而将线面求交的搜索空间由二维降至一维,使算法的时间复杂度由基本方法的O(n2)降至O(n)。基于Direct3D和VC++开发了相应试验系统,验证了该算法的正确性和效率。The algorithms concerning the real-time picking of ground coordinates in 3D scene were investigated in this paper. By setting a reference projection plane for terrain, the correspondence between the triangles intersected with a given ray and the triangles intersected with the projection line of the ray was established. Based on the correspondence mentioned above, an algorithm for picking the ground coordinates was proposed. The testing space of intersection between spatial lines and triangles was reduced to one-dimension from two-dimension, and its time complexity was improved to O（ n） from O（ n2）. The correctness and the efficiency of the algorithm were tested by a system developed by using Direct3D and VC＋＋.

关 键 词：三维场景 地面坐标 实时拾取 射线投影 三维量算 

分 类 号：P208[天文地球—地图制图学与地理信息工程] TP391.41[天文地球—测绘科学与技术]