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arXiv · 1805.09048

Area-preserving parameterizations for spherical ellipses

Ibón Guillén·Carlos Ureña·Alan King·Marcos Fajardo·Iliyan Georgiev·Jorge López-Moreno·Adrian Jarabo
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Abstract

We present new methods for uniformly sampling the solid angle subtended by a disk. To achieve this, we devise two novel area-preserving mappings from the unit square $[0,1]^2$ to a spherical ellipse (i.e. the projection of the disk onto the unit sphere). These mappings allow for low-variance stratified sampling of direct illumination from disk-shaped light sources. We discuss how to efficiently incorporate our methods into a production renderer and demonstrate the quality of our maps, showing significantly lower variance than previous work.

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Ibón Guillén, Carlos Ureña, Alan King, Marcos Fajardo, Iliyan Georgiev, Jorge López-Moreno, Adrian Jarabo. 2018-05-23. Area-preserving parameterizations for spherical ellipses. https://doi.org/10.1111/cgf.13234

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