【作者】 李炳炎； 何芒； 徐晓文； 章传芳； 孙厚军；

【Author】 LI Bing-yan;HE Mang;XU Xiao-wen;ZHANG Chuan-fang;SUN Hou-jun;School of information and electronic, Beijing institute of technology;

【机构】 北京理工大学信息与电子学院；

【摘要】 矩量法(MoM)与物理光学方法(PO)混合时,需要准确快速地判断PO区域在点光源照射下的亮区和暗区,为此需要构造一种高效率的遮挡消隐算法。传统的遮挡消隐算法是判断每两个三角形之间是否遮挡,需要耗费大量时间。本文对基于计算机图形学中的Z-buffer算法进行了改进。通过对比模型三角面片被遮挡的面积比,在保证精度情况下判断三角面片是否遮挡,并利用包围盒作为投影背景平面降低内存用量。经数值实验测试,这种算法在保证精度的前提下,相比传统Z-buffer算法计算速度有了较大提升,内存使用量也相应减少很多。更多还原

【Abstract】 When applying the MoM-PO hybrid method, it is necessary to judge the lit region and the shadowed region in the PO area. Therefore, an effective shadowing algorithm is required to provide fast and accurate judgment. The traditional shadowing algorithm judges the shadowing relationship of each two facets, thus consuming too much time. This paper proposes a highly efficient method which is based on the improved Z-buffer algorithm. By comparing the area ratio of shadowed facets, it could be found whether the facets are shadowed or not, which literally guarantees the accuracy of the judgment. The bounding box is simultaneously utilized as the projection background to reduce memory usage. The proposed algorithm shows great advantages over the traditional one, especially in its high running speed. A numerical experiment demonstrated that thi s new algorithm could guarantee the good computational accuracy with much less time and memory consumption.更多还原