利用深度图优化的自然光束体构建与绘制  

Optimized Construction and Rendering of Natural Light Shaft Volumes through Depth Map

作　　者：李思宇[1] 李胜[1] 王衡[1] 汪国平[1] 

机构地区：[1]北京大学信息科学技术学院机器感知与智能教育部重点实验室,北京100871

出　　处：《计算机辅助设计与图形学学报》2011年第7期1123-1130,共8页Journal of Computer-Aided Design & Computer Graphics

基　　金：国家"九七三"重点基础研究发展计划项目(2010CB328002);国家自然科学基金(60833007;90915010);湖南大学汽车车身先进设计制造国家重点实验室开放基金(30815006)

摘　　要：为了模拟由散射形成的自然光束,提出基于深度图的光束体优化构建和实时绘制算法.首先把阴影体视作特殊的光束体参与计算,实现光束被物体遮挡的光照与阴影交错的效果;其次利用深度图在GPU中消除重叠的阴影体,降低填充率,优化复杂场景中多个阴影体与光束体相交情况的绘制效果.该算法将自然光束体构建中的一部分提前到预处理中完成,另一部分在GPU内核实现,提高了效率,再结合GPU上高效的散射计算绘制出动态光源产生的自然光束效果;此外,添加了大气中因散射可见的尘埃粒子的模拟,进一步增强了真实感.对动态光源下多个场景的实验结果表明,文中算法解决了散射光束中的遮挡与阴影问题,有效地模拟了光影交错的综合效果,并具有实时性.In this paper,an efficient method is proposed for constructing and simulating dynamic natural light shaft volumes with atmospheric scattering.First,to represent the obstructed light shafts,the shadow volumes are considered as special light shaft volumes.Then the information in depth map is used to eliminate the complex overlapping between shadow volumes so that the fill-rate consumption of rasterization is reduced.We preprocess some construction steps of light shafts and the remainder are implemented in GPU kernel.The scattering process is efficiently computed on GPU.This algorithm can afford realistic simulation of complex scene with dynamic light source in real-time.We also simulate the visible dust floating in the air due to scattering to enhance the reality.Experimental results showed that the proposed algorithm offers an efficient solution to the occlusion and shadow problem and simulates the combined effect of natural light and shadow in real time.

关 键 词：光束体 散射 阴影体 深度图 图形处理器 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]