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A geometry-based soft shadow volume algorithm using graphics hardware

Assarsson, Ulf and Akenine-Möller, Tomas LU (2003) 30th International Conference on Computer Graphics and Interactive Techniques, 2003 In ACM Transactions on Graphics 22(3). p.511-520
Abstract
Most previous soft shadow algorithms have either suffered from aliasing, been too slow, or could only use a limited set of shadow casters and/or receivers. Therefore, we present a strengthened soft shadow volume algorithm that deals with these problems. Our critical improvements include robust penumbra wedge construction, geometry-based visibility computation, and also simplified computation through a four-dimensional texture lookup. This enables us to implement the algorithm using programmable graphics hardware, and it results in images that most often are indistinguishable from images created as the average of 1024 hard shadow images. Furthermore, our algorithm can use both arbitrary shadow casters and receivers. Also, one version of our... (More)
Most previous soft shadow algorithms have either suffered from aliasing, been too slow, or could only use a limited set of shadow casters and/or receivers. Therefore, we present a strengthened soft shadow volume algorithm that deals with these problems. Our critical improvements include robust penumbra wedge construction, geometry-based visibility computation, and also simplified computation through a four-dimensional texture lookup. This enables us to implement the algorithm using programmable graphics hardware, and it results in images that most often are indistinguishable from images created as the average of 1024 hard shadow images. Furthermore, our algorithm can use both arbitrary shadow casters and receivers. Also, one version of our algorithm completely avoids sampling artifacts which is rare for soft shadow algorithms. As a bonus, the four-dimensional texture lookup allows for small textured light sources, and, even video textures can be used as light sources. Our algorithm has been implemented in pure software, and also using the GeForce FX emulator with pixel shaders. Our software implementation renders soft shadows at 0.5-5 frames per second for the images in this paper. With actual hardware, we expect that our algorithm will render soft shadows in real time. An important performance measure is bandwidth usage. For the same image quality, an algorithm using the accumulated hard shadow images uses almost two orders of magnitude more bandwidth than our algorithm. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
graphics hardware, soft shadows, pixel shaders
in
ACM Transactions on Graphics
volume
22
issue
3
pages
511 - 520
publisher
ACM
conference name
30th International Conference on Computer Graphics and Interactive Techniques, 2003
external identifiers
  • scopus:1642449634
ISSN
0730-0301
DOI
10.1145/882262.882300
language
English
LU publication?
yes
id
93b51157-23c1-4c99-99d3-b6a087b71079 (old id 596108)
date added to LUP
2007-11-26 08:36:33
date last changed
2017-07-23 04:50:22
@inproceedings{93b51157-23c1-4c99-99d3-b6a087b71079,
  abstract     = {Most previous soft shadow algorithms have either suffered from aliasing, been too slow, or could only use a limited set of shadow casters and/or receivers. Therefore, we present a strengthened soft shadow volume algorithm that deals with these problems. Our critical improvements include robust penumbra wedge construction, geometry-based visibility computation, and also simplified computation through a four-dimensional texture lookup. This enables us to implement the algorithm using programmable graphics hardware, and it results in images that most often are indistinguishable from images created as the average of 1024 hard shadow images. Furthermore, our algorithm can use both arbitrary shadow casters and receivers. Also, one version of our algorithm completely avoids sampling artifacts which is rare for soft shadow algorithms. As a bonus, the four-dimensional texture lookup allows for small textured light sources, and, even video textures can be used as light sources. Our algorithm has been implemented in pure software, and also using the GeForce FX emulator with pixel shaders. Our software implementation renders soft shadows at 0.5-5 frames per second for the images in this paper. With actual hardware, we expect that our algorithm will render soft shadows in real time. An important performance measure is bandwidth usage. For the same image quality, an algorithm using the accumulated hard shadow images uses almost two orders of magnitude more bandwidth than our algorithm.},
  author       = {Assarsson, Ulf and Akenine-Möller, Tomas},
  booktitle    = {ACM Transactions on Graphics},
  issn         = {0730-0301},
  keyword      = {graphics hardware,soft shadows,pixel shaders},
  language     = {eng},
  number       = {3},
  pages        = {511--520},
  publisher    = {ACM},
  title        = {A geometry-based soft shadow volume algorithm using graphics hardware},
  url          = {http://dx.doi.org/10.1145/882262.882300},
  volume       = {22},
  year         = {2003},
}