A Survey of Real-time Soft Shadows Algorithms
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Date
2003
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Journal ISSN
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Publisher
Blackwell Publishing, Inc and Eurographics Association
Abstract
Recent advances in GPU technology have produced a shift in focus for real-time rendering applications, whereby
improvements in image quality are sought in addition to raw polygon display performance. Rendering effects
such as antialiasing, motion blur and shadow casting are becoming commonplace and will likely be considered
indispensable in the near future. The last complete and famous survey on shadow algorithms — by Woo et al. [52]
in 1990 — has to be updated in particular in view of recent improvements in graphics hardware, which make new
algorithms possible. This paper covers all current methods for real-time shadow rendering, without venturing into
slower, high quality techniques based on ray casting or radiosity. Shadows are useful for a variety of reasons: first,
they help understand relative object placement in a 3D scene by providing visual cues. Second, they dramatically
improve image realism and allow the creation of complex lighting ambiances. Depending on the application, the
emphasis is placed on a guaranteed framerate, or on the visual quality of the shadows including penumbra effects
or “soft shadows”. Obviously no single method can render physically correct soft shadows in real time for any
dynamic scene! However our survey aims at providing an exhaustive study allowing a programmer to choose the
best compromise for his/her needs. In particular we discuss the advantages, limitations, rendering quality and
cost of each algorithm. Recommendations are included based on simple characteristics of the application such
as static/moving lights, single or multiple light sources, static/dynamic geometry, geometric complexity, directed
or omnidirectional lights, etc. Finally we indicate which methods can efficiently exploit the most recent graphics
hardware facilities.
Description
@article{10.1111:j.1467-8659.2003.00722.x,
journal = {Computer Graphics Forum},
title = {{A Survey of Real-time Soft Shadows Algorithms}},
author = {Hasenfratz, J. -M. and Lapierre, M. and Holzschuch, N. and Sillion, F. and Artis GRAVIR/IMAG-INRIA},
year = {2003},
publisher = {Blackwell Publishing, Inc and Eurographics Association},
ISSN = {1467-8659},
DOI = {10.1111/j.1467-8659.2003.00722.x}
}