Advertisement

Opacity Shadow Maps

  • Tae-Yong Kim
  • Ulrich Neumann
Part of the Eurographics book series (EUROGRAPH)

Abstract

Opacity shadow maps approximate light transmittance inside a complex volume with a set of planar opacity maps. A volume made of standard primitives (points, lines, and polygons) is sliced and rendered with graphics hardware to each opacity map that stores alpha values instead of traditionally used depth values. The alpha values are sampled in the maps enclosing each primitive point and interpolated for shadow computation. The algorithm is memory efficient and extensively exploits existing graphics hardware. The method is suited for generation of self-shadows in discontinuous volumes with explicit geometry, such as foliage, fur, and hairs. Continuous volumes such as clouds and smoke may also benefit from the approach.

Keywords

Transmittance Function Graphic Hardware Depth Buffer Discontinuous Volume Volumetric Object 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. [1]
    J. F. Blinn, Light reflection functions for simulation of clouds and dusty surfaces, SIGGRAPH Proceedings, Vol. 16, pp. 21–29,1982.CrossRefGoogle Scholar
  2. [2]
    M. Bolin and G. W. Meyer, A frequency based ray tracer, SIGGRAPH Proceedings, Vol. 29, pp. 409–418,1995.Google Scholar
  3. [3]
    R. Drebin, L. Carpenter, and P. Hanrahan, Volume rendering, SIGGRAPH Proceedings, Vol. 22, pp. 65–74,1988.CrossRefGoogle Scholar
  4. [4]
    J. Foley, A. Van Dam, S. K. Feiner, and J. F. Hughes, Computer graphics, principles and practice, Second Edition, Addison-Wesley, July, 1995.Google Scholar
  5. [5]
    A. S. Glassner, An introduction to ray tracing, Academic Press, 1993Google Scholar
  6. [6]
    J. Kajiya and B. P. Herzen, Ray tracing volume densities, SIGGRAPH Proceedings, Vol. 18, pp. 165–174,1984.CrossRefGoogle Scholar
  7. [7]
    J. Kajiya and T. Kay, Rendering fur with three dimensional textures, SIGGRAPH Proceedings, Vol. 23, pp. 271–280, 1989.CrossRefGoogle Scholar
  8. [8]
    M. Levoy, Display of surfaces from volume data, Ph.D. thesis, University of North Carolina at Chapel Hill, 1989.Google Scholar
  9. [9]
    J. P. Lewis, Disney TSL, Personal communication.Google Scholar
  10. [10]
    T. Lokovic and E. Veach, Deep shadow maps, SIGGRAPH Proceedings, Vol. 34, pp. 385–392,2000.CrossRefGoogle Scholar
  11. [11]
    S. N. Pattanaik and S. P. Mudur, Computation of global illumination in a participating medium by Monte Carlo simulation, The Journal of Visualization and Computer Animation, Vol. 4(3), pp. 133–152, John Wiley & sons, 1993.CrossRefGoogle Scholar
  12. [12]
    W. T. Reeves, D. H. Salesin, and R. L. Cook, Rendering antialiased shadows with depth maps, SIGGRAPH Proceedings, Vol. 21, pp. 283–291,1987.CrossRefGoogle Scholar
  13. [13]
    L. Williams, Casting curved shadows on curved surfaces, SIGGRAPH Proceedings, Vol. 12, pp. 270–274, August, 1978.CrossRefGoogle Scholar
  14. [14]
    A. Woo, P. Poulin, and A. Fournier, A survey of shadow algorithms, IEEE Computer Graphics and Applications, 10(6), pp. 13–32, November, 1990.CrossRefGoogle Scholar
  15. [15]
    H. Zhang, Forward shadow mapping, Rendering Techniques’ 98, Vol. 9, pp. 131–138, Springer-Verlag, 1998.CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Wien 2001

Authors and Affiliations

  • Tae-Yong Kim
    • 1
  • Ulrich Neumann
    • 1
  1. 1.Computer Graphics and Immersive Technology Laboratory, Integrated Media Systems CenterUniversity of Southern CaliforniaUSA

Personalised recommendations