Vector occluders: an empirical approximation for rendering global illumination effects in real-time
Date
2013-02-01
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Abstract
Precomputation has been previously used as a means to get global illumination effects
in real-time on consumer hardware of the day. Our work uses Sloan’s 2002 PRT method
as a starting point, and builds on it with two new ideas.
We first explore an alternative representation for PRT data. “Cpherical harmonics”
(CH) are introduced as an alternative to spherical harmonics, by substituting the
Chebyshev polynomial in the place of the Legendre polynomial as the orthogonal
polynomial in the spherical harmonics definition. We show that CH can be used instead
of SH for PRT with near-equivalent performance.
“Vector occluders” (VO) are introduced as a novel, precomputed, real-time, empirical
technique for adding global illumination effects including shadows, caustics and
interreflections to a locally illuminated scene on static geometry. VO encodes PRT data
as simple vectors instead of using SH. VO can handle point lights, whereas a standard
SH implementation cannot.
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Keywords
Global illumination, Real-time, Shadows, Caustics, Interreflections