33 Point Samples - 156 FPS
9 Line Samples - 210 FPS
1 Area Sample - 240 FPS
Obscurance and Ambient Occlusion (AO) are popular techniques in both film
and games that model how ambient light is shadowed. While it is largely a
solved problem for static scenes, for dynamic scenes it is still difficult to
compute at interactive rates. Recent attempts to compute AO in screen space for
dynamic scenes either have poor performance or suffer from under-sampling
problems. We formulate the problem as a 3D volumetric integral, which maps
more naturally to graphics hardware. This integral can be solved using line
samples to improve the under-sampling problems that plague other techniques.
Following the idea of line integrals to its logical conclusion, we show results
using area samples that use a simple statistical model of the depth buffer that
allows us to use a single sample. We also discuss strategies for generating
point, line, and area sample patterns along with ways to incorporate the
surface normal into the volume obscurance calculation.