Metzgar,J.B., Semwal,S.K.
Abstract:
Scalable Spherical Harmonics Hierarchies (SSPHH) is a real-time rendering solution to the global illumination problem. Our novel method is a system of components that enables the computation of light probes and the conversion to spherical harmonics coefficients, which are used as anisotropic time-varying light sources we call Spherical Harmonics Lights (SPHLs). The SPHLs encode irradiance information that can be used for image-based lighting. Our approach focuses on reconstructing scene lighting using diffuse illumination but is flexible to allow specular details. Furthermore, we consider the light transport from neighboring SPHLs by computing a transfer coefficient that estimates how much light from one probe is visible at another. SPHLs can be used for physically-based lighting using rendering methods similar to point lights and shadow maps. We created a reproducible testing methodology to compare our images with those of a commercial path tracer by automatically generating the appropriate scene information which gets used with absolute error metrics to determine remaining image defects. Our SSPHH method utilizes a scalable architecture to distribute the rendering of light probes between client and worker nodes using the ZeroMQ Majordomo protocol.