Presampled visibility for ambient occlusion
Date issued
2008
Journal Title
Journal ISSN
Volume Title
Publisher
Václav Skala - UNION Agency
Abstract
We present a novel method to accelerate the computation of the visibility function of the lighting equation, in
dynamic scenes composed of rigid, non-penetrating objects. The main idea of the technique is to pre-compute
for each object in the scene its associated four-dimensional field that describes the visibility in each direction for
all positional samples on a sphere around the object, we call this a displacement field. We are able to speed up
the calculation of algorithms that trace visibility rays to near real time frame rates. The storage requirements of
the technique, amounts from one byte to one bit per ray direction making it particularly attractive to scenes with
multiple instances of the same object, as the same cached data can be reused, regardless of the geometric
transformation applied to each instance. We suggest an acceleration technique and identify the sampling method
that gives the best results based on experimentation.
Description
Subject(s)
nepřímé osvětlení, viditelnost, rovnoměrné rozdělení, polokoule, okolní okluze, sledování paprsku
Citation
Journal of WSCG. 2008, vol. 16, no. 1-3, p. 17-24.