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.



@article{Guillen:2017:Ellipses, author = {Guill\'{e}n, Ib\'{o}n and Ure\~{n}a, Carlos and King, Alan and Fajardo, Marcos and Georgiev, Iliyan and L\'{o}pez-Moreno, Jorge and Jarabo, Adrian}, journal = {Computer Graphics Forum (Proceedings of EGSR)}, title = {Area-Preserving Parameterizations for Spherical Ellipses}, volume = {36}, number = {4}, year = {2017} }