Advertisement

Forward Shadow Mapping

  • Hansong Zhang
Part of the Eurographics book series (EUROGRAPH)

Abstract

Forward shadow mapping is a new approach to real-time shadow generation. The traditional shadow map algorithm maps the pixels in the eye’s view backward into the depth buffers of light sources (i.e. shadow maps), which is similiar to and often implemented as an extension to texture mapping. Our algorithm reverses this process by using 3-D image warping techniques to transform shadow map pixels forward into the eye’s view to directly indicate which pixels are lit; it does not interfere with normal texture mapping and easily supports antialiased shadow edges and projective textures. Access to shadow maps and projective textures is in pixel-sequential order. This algorithm has advantages when speed of texture mapping becomes the performance bottleneck, which is often the case in visual simulation and game applications.

Keywords

Computer Graphic Texture Mapping Depth Buffer Soft Shadow Destination Image 
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. Ake93.
    Kurt Akeley. RealityEngine graphics. In Computer Graphics (SIGGRAPH’ 93 Proceedings), volume 27, pages 109–116, August 1993.Google Scholar
  2. App68.
    A. Appel. Some techniques for shading machine renderings of solids. In IFIP, volume 32, pages 37–45, 1968.Google Scholar
  3. AWG78.
    P. Atherton, K. Weiler, and D. Greenberg. Polygon shadow generation. In Computer Graphics (SIGGRAPH’ 78 Proceedings), volume 12, pages 275–281, August 1978.CrossRefGoogle Scholar
  4. BB84.
    L. S. Brotman and N. I. Badler. Generating soft shadows with a depth buffer algorithm. IEEE Computer Graphics and Applications, 4(10):71–81, October 1984.Google Scholar
  5. Ber86.
    P. Bergeron. A general version of crow’S shadow volumes. IEEE Computer Graphics and Applications, 6(9):17–28, 1986.CrossRefGoogle Scholar
  6. BK70.
    W. J. Bouknight and K. C. Kelly. An algorithm for producing half-tone computer graphics presentations with shadows and movable light sources. In Proc. AFIPS JSCC, volume 36, pages 1–10, 1970.Google Scholar
  7. CF89.
    Norman Chin and Steven Feiner. Near real-time shadow generation using BSP trees. In Computer Graphics (SIGGRAPH’ 89 Proceedings), volume 23, pages 99–106, July 1989.CrossRefGoogle Scholar
  8. CF92.
    Norman Chin and Steven Feiner. Fast object-precision shadow generation for areal light sources using BSP trees. In Computer Graphics (1992 Symposium on Interactive 3D Graphics), volume 25, pages 21–30, March 1992.Google Scholar
  9. CG85.
    Michael F. Cohen and Donald P. Greenberg. The Hemi-Cube: A radiosity solution for complex environments. In Computer Graphics (SIGGRAPH’ 85 Proceedings), volume 19, pages 31–40, August 1985.CrossRefGoogle Scholar
  10. Cro77.
    Franklin C. Crow. Shadow algorithms for computer graphics. In Computer Graphics (SIGGRAPH’ 77 Proceedings), volume 11, pages 242–248, July 1977.CrossRefGoogle Scholar
  11. CW93.
    Shenchang Eric Chen and Lance Williams. View interpolation for image synthesis. In Computer Graphics (SIGGRAPH’ 93 Proceedings), volume 27, pages 279–288, August 1993.Google Scholar
  12. DSV97.
    Lucia Darsa, Bruno C. Silva, and Amitabh Varshney. Navigating static environments using image-space simplification and morphing. In 1997 Symposium on Interactive 3D Graphics, pages 7–16, April 1997.Google Scholar
  13. DWS88.
    Michael Deering, Stephanie Winner, Bic Schediwy, Chris Duffy, and Neil Hunt. The triangle processor and normal vector shader: A VLSI system for high performance graphics. In Computer Graphics (SIGGRAPH’ 88 Proceedings), volume 22, pages 21–30, August 1988.CrossRefGoogle Scholar
  14. EMP97.
    John Eyles, Steven Molnar, John Poulton, Trey Greer, Anselmo Lastra, Nick England, and Lee Westover. PixelFlow: The realization. In 1997 SIGGRAPH / Eurographics Workshop on Graphics Hardware, pages 57–68. ACM SIGGRAPH / Eurographics, ACM Press, August 1997.Google Scholar
  15. FGH85.
    Henry Fuchs, Jack Goldfeather, Jeff P. Hultquist, Susan Spach, John D. Austin, Frederick P. Brooks, Jr., John G. Eyles, and John Poulton. Fast spheres, shadows, textures, transparencies, and image enhancements in Pixel-Planes. In Computer Graphics (SIGGRAPH’ 85 Proceedings), volume 19, pages 111–120, July 1985.CrossRefGoogle Scholar
  16. GHC97.
    Steven Gortler, Liwei He, and Michael F. Cohen. Rendering layered depth images. Technical Report MSR-TR-97-09, Microsoft Research, 1997.Google Scholar
  17. GTGB84.
    Cindy M. Goral, Kenneth E. Torrance, Donald P. Greenberg, and Bennett Battaile. Modelling the interaction of light between diffuse surfaces. In Computer Graphics (SIGGRAPH’ 84 Proceedings), volume 18, pages 212–222, July 1984.CrossRefGoogle Scholar
  18. Hei91.
    Tim Heidmann. Real shadows, real time. Iris Universe, 18:28–31, 1991.Google Scholar
  19. HH97.
    Paul S. Heckbert and Michael Herf. Simulating soft shadows with graphics hardware. Technical Report CMU-CS-97-104, School of Computer Sciene, Carnegie Mellon University, 1997.Google Scholar
  20. HN85.
    J. C. Hourcade and A. Nicolas. Algorithms for antialiased cast shadows. Computers and Graphics, 9(3):259–265, 1985.CrossRefGoogle Scholar
  21. Kay79.
    Douglas S. Kay. Transparency, refraction, and ray tracing for computer synthesized images. Master’s thesis, Cornell U., January 1979.Google Scholar
  22. Max86.
    Nelson L. Max. Atmospheric illumination and shadows. In Computer Graphics (SIGGRAPH’ 86 Proceedings), volume 20, pages 117–124, August 1986.CrossRefGoogle Scholar
  23. MB95.
    Leonard McMillan and Gary Bishop. Plenoptic modeling: An image-based rendering system. In Computer Graphics (SIGGRAPH’ 95 Proceedings), pages 39–46. ACM SIGGRAPH, August 1995.Google Scholar
  24. McR96.
    Organizer: Tom McReynolds. Programming with opengl: Advanced rendering. SIG-GRAPH’96 Course Notes, pages 27–28, August 1996.Google Scholar
  25. MMB97.
    William R. Mark, Leonard McMillan, and Gary Bishop. Post-rendering 3d warping. In 1997 Symposium on Interactive 3D Graphics, pages 7–16, April 1997.Google Scholar
  26. NN85.
    Tomoyuki Nishita and Eihachiro Nakamae. Continuous tone representation of three-dimensional objects taking account of shadows and interreflection. In Computer Graphics (SIGGRAPH’ 85 Proceedings), volume 19, pages 23–30, July 1985.CrossRefGoogle Scholar
  27. RSC87.
    William T. Reeves, David H. Salesin, and Robert L. Cook. Rendering antialiased shadows with depth maps. In Computer Graphics (SIGGRAPH’ 87 Proceedings), volume 21, pages 283–291, July 1987.CrossRefGoogle Scholar
  28. SDB97.
    François Sillion, George Drettakis, and Benoit Bodelet. Efficient impostor manipulation for real-time visualization of urban scenery. In Computer Graphics Forum (Proc. of Eurographics’ 97), volume 16, pages 207–218, Budapest, Hungary, September 1997.CrossRefGoogle Scholar
  29. SKW92.
    Mark Segal, Carl Korobkin, Rolf van Widenfelt, Jim Foran, and Paul E. Haeberli. Fast shadows and lighting effects using texture mapping. In Computer Graphics (SIGGRAPH’ 92 Proceedings), volume 26, pages 249–252, July 1992.CrossRefGoogle Scholar
  30. TN85.
    E. Nakamae T. Nishita, I. Okamura. Continuous tone representation of three-dimensional objects taking account of shadows and interreflection. ACM Transaction on Graphics, 20(2): 123–146, April 1985.Google Scholar
  31. Wes90.
    Lee Westover. Footprint evaluation for volume rendering. In Computer Graphics (SIGGRAPH’ 90 Proceedings), volume 24, pages 367–376, August 1990.CrossRefGoogle Scholar
  32. Whi79.
    T. Whitted. An improved illumination model for shaded display. In Computer Graphics (Special SIGGRAPH’ 79 Issue), volume 13, pages 1–14, August 1979.CrossRefGoogle Scholar
  33. Wil78.
    Lance Williams. Casting curved shadows on curved surfaces. In Computer Graphics (SIGGRAPH’ 78 Proceedings), volume 12, pages 270–274, August 1978.CrossRefGoogle Scholar
  34. WND85.
    Mason Woo, Jackie Neider, and Tom Davis. OpenGL Programming Guide, 2nd Edition. Addison-Wesley, 1985.Google Scholar
  35. WPF90.
    Andrew Woo, Pierre Poulin, and Alain Fournier. A survey of shadow algorithms. IEEE Computer Graphics and Applications, 10(6): 13–32, November 1990.CrossRefGoogle Scholar
  36. Zha97.
    Hansong Zhang. A traditionalist view of 3-d image warping. Technical Report 97-043, Department of Computer Sciene, UNC-Chapel Hill, September 1997.Google Scholar

Copyright information

© Springer-Verlag Wien 1998

Authors and Affiliations

  • Hansong Zhang
    • 1
  1. 1.Department of Computer ScienceUniversity of North CarolinaChapel HillUSA

Personalised recommendations