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Caustic Forecasting: Unbiased Estimation of Caustic Lighting for Global Illumination
Author(s) -
Budge B. C.,
Anderson J. C.,
Joy K. I.
Publication year - 2008
Publication title -
computer graphics forum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.578
H-Index - 120
eISSN - 1467-8659
pISSN - 0167-7055
DOI - 10.1111/j.1467-8659.2008.01345.x
Subject(s) - caustic (mathematics) , global illumination , rendering (computer graphics) , photon , computer science , path tracing , ray tracing (physics) , computer graphics (images) , specular reflection , radiosity (computer graphics) , optics , computer vision , physics , mathematics , geometry
We present an unbiased method for generating caustic lighting using importance sampled Path Tracing with Caustic Forecasting . Our technique is part of a straightforward rendering scheme which extends the Illumination by Weak Singularities method to allow for fully unbiased global illumination with rapid convergence. A photon shooting preprocess, similar to that used in Photon Mapping, generates photons that interact with specular geometry. These photons are then clustered, effectively dividing the scene into regions which will contribute similar amounts of caustic lighting to the image. Finally, the photons are stored into spatial data structures associated with each cluster, and the clusters themselves are organized into a spatial data structure for fast searching. During rendering we use clusters to decide the caustic energy importance of a region, and use the local photons to aid in importance sampling, effectively reducing the number of samples required to capture caustic lighting.