作　　者： ; ; ;

机构地区： 清华大学软件学院

出　　处： 《计算机辅助设计与图形学学报》 2011年第1期54-61,共8页

摘　　要： 现有渲染复杂光源光照的技术大多需要一个长时间的预处理阶段,一些不需要预处理的技术往往只专注某一类型的光照效果.为了解决不同类型光照计算需要不同类型采样策略的问题,提出一个新的、不需预计算的高效渲染复杂光源光照的框架.通过对渲染方程进行分治采样,统一的光照计算被分解为高频反射、低频反射以及遮挡阴影3项,每一项采用不同的采样策略计算,以使各部分都能在较短的时间内得到高质量的渲染结果.高频反射项根据材质BRDF的特性进行重要性采样;低频反射项是以光源亮度作为采样权重对光源进行预采样计算得到的;遮挡项的结果由屏幕空间的深度信息采样计算得到.由于遮挡阴影的低频特性,间隔采样技术可以在保持视觉效果的同时大大减少每个像素的采样数量.此渲染框架易于在GPU上实现,且可以解决很多实时渲染问题.实验结果以及对比表明,应用该技术框架能够处理完整的复杂光照效果,且达到比现有技术更高的渲染质量. Existing methods for real-time illumination of complex lights,either require long time pre-computation,or only focus on some special types of illumination.Because computing different kinds of illumination requires different sampling strategies,this paper introduces a novel efficient framework for rendering illumination of complex light sources,in which the pre-computation is not necessary.We divide the rendering equation into three parts： high-frequency term,low-frequency term and occlusion term.Each term is computed by a proper sampling strategy.High-frequency term is solved by importance sampling the BRDF,while low-frequency term is computed by importance sampling the light sources.Occlusion term is computed with depth information in screen-space,and the required number of samples is greatly reduced by interleaved sampling.Our framework is easy to implement on GPU and can solve many real-time rendering problems.The results show that our technique can handle complete light effects with higher quality than previous works.

关 键 词： 实时渲染 重要性采样 复杂光源 环境映射

领　　域： [自动化与计算机技术] [自动化与计算机技术]