Virtual Spherical Gaussian Lights for Real-time Glossy Indirect Illumination

• Published in: Computer graphics forum Vol. 34; no. 7; pp. 89 - 98
• Main Author: Tokuyoshi, Yusuke
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Publishing Ltd 01.10.2015
• Subjects: and texture; Approximation; Categories and Subject Descriptors (according to ACM CCS); Computer science; Gaussian; Glossy; I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism-Color; I.3.7 [Computer Graphics]: Three‐Dimensional Graphics and Realism—Color, shading, shadowing, and texture; Illumination; Image processing systems; Mathematical analysis; Real time; shading; shadowing; Studies; Texture; United States > US
• ISSN: 0167-7055; 1467-8659
• DOI: 10.1111/cgf.12748

Virtual point lights (VPLs) are well established for real‐time global illumination. However, this method suffers from spiky artifacts and flickering caused by singularities of VPLs, highly glossy materials, high‐frequency textures, and discontinuous geometries. To avoid these artifacts, this paper introduces a virtual spherical Gaussian light (VSGL) which roughly represents a set of VPLs. For a VSGL, the total radiant intensity and positional distribution of VPLs are approximated using spherical Gaussians and a Gaussian distribution, respectively. Since this approximation can be computed using summations of VPL parameters, VSGLs can be dynamically generated using mipmapped reflective shadow maps. Our VSGL generation is simple and independent from any scene geometries. In addition, reflected radiance for a VSGL is calculated using an analytic formula. Hence, we are able to render one‐bounce glossy interreflections at real‐time frame rates with smaller artifacts.