一种复杂非直接光照场景的渲染算法

Algorithm for Scenes with Complex Indirect Illumination

针对一类具有复杂非直接光照的场景,提出了一种称作Ercuts的全局光照算法。算法提出了虚拟点光源模拟ER采样路径的思想,首先使用双向路径跟踪初始化场景,再根据ER采样在每个像素处产生长度相等的Markov链,这充分利用了双向路径之间的相关性。算法还引入了一种加速虚拟点光源光照计算的方法,为场景中的虚拟点光源建立光源树,通过遍历光源树并控制误差上界来计算场景光照。实验表明,与传统的双向路径跟踪相比,算法在具有复杂非直接光照的场景中有较好表现。

A global illumination algorithm called Ercuts was proposed to render scenes with complex indirect illumination.Ercuts adopted bidirectional path tracing to initialize the scene,and generated Markov chains of the same length by ER（Energy Redistribution） sampling for each pixel.After that,a VPL（Virtual Point Light） set was developed to simulate Markov chains.Ercuts also accelerated the computation of VPLs by establishing a light tree from VPL set and tra-versing it to approximate illumination from VPLs with a strongly sublinear cost.The experimental results indicate that,compared with traditional bidirectional path tracing,Ercuts works more effectively for scenes with complex indirect illumination.