Abstract
This paper proposes an efficient importance sampling method of virtual point lights (VPLs) for many-light rendering by constructing probability distributions proportional to the contributions of VPLs. In many-light rendering methods, direct illumination and indirect illumination incident onto shading points are approximated by the contributions of VPLs. The proposed method employs an importance caching method to construct probability distributions of sampling VPLs. The importance caching method records the contributions of VPLs at each cache point to construct probability distributions. The importance caching method, however, generates cache points randomly, which makes it difficult to obtain probability distributions proportional to the contributions of VPLs at shading points where the variations of contributions from VPLs to nearby cache points are large. To address this problem, the proposed method distributes cache points adaptively for such regions to construct probability distributions proportional to contributions of VPLs, resulting in rendering less noise images with the same number of VPLs.
