
258 16. HDR Image-BasedLighting on the Web
aswell as ltering artifacts, which can be dicult to fully mask. Dual paraboloid mapping
[Heidrich 98] avoids this polar distortion, having only modest discontinuities. It does,
however, provoke somewhat uneven texel distribution and does not make ecient use of
texture space, as much goes unused around its circular borders.
Octahedral environment mapping [Engelhardt 08] provides a good compromise
between simplicity, distortion, and speed, with performance and appearance very similar
to cube mapping. Additionally, its two-dimensional surface lies in a perfect square, which
means no space goes unus ...