基于轮廓边拟合的软影映射算法  

Soft Shadow Mapping by Line Fitting

作　　者：刘浏[1,2] 周炜[1] 李华[1] 

机构地区：[1]中国科学院计算技术研究所集成应用中心,北京100190 [2]中国科学院研究生院,北京100049

出　　处：《计算机辅助设计与图形学学报》2012年第12期1533-1541,共9页Journal of Computer-Aided Design & Computer Graphics

基　　金：国家"八六三"高技术研究发展计划(2007AA01Z317)

摘　　要：针对实时软影映射算法在绘制大面积光源时绘制效率不高的问题,提出一种基于轮廓边拟合的快速软影映射算法.该算法在场景阴影映射图中的固定尺寸的块内拟合轮廓边直线,并用一种层次化的数据结构来保存拟合的轮廓边直线;再利用反投影轮廓边直线的方法快速地计算着色点的可见性,生成真实的软影效果.实验结果表明,与现有的算法相比,文中算法在不显著降低软影质量的基础上有效地提高了绘制效率.Rendering high quality shadows with large penumbra in real-time is a challenging problem. In this paper, we propose a new edge extracting method with a new data structure to attack this problem and provide an efficient and practical technique for soft shadow generation. First, a multi-pass method to fit edge lines in a fixed size block containing edge pixels is presented, and then a hierarchical texture map saving these lines entitled hierarchical edge map （HEM） is employed. Finally the visibility is computed by back-projecting these lines in HEM onto the 2D light source domain to generate realistic soft shadow. The rendering performance is greatly improved, while keeping the soft shadow quality.

关 键 词：实时软影 面光源 轮廓边提取 轮廓边拟合 反投影 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]