Skip to main content
SpringerLink
Log in

A hybrid approach to interactive global illumination and soft shadows

  • Original Article
  • Published:
The Visual Computer Aims and scope Submit manuscript

Abstract

We present a hybrid approach to simulate global illumination and soft shadows at interactive frame rates. The strengths of hardware-accelerated GPU techniques are combined with CPU methods to achieve physically consistent results while maintaining reasonable performance. The process of image synthesis is subdivided into multiple passes accounting for the different illumination effects. While direct lighting is rendered efficiently by rasterization, soft shadows are simulated using a novel approach combining the speed of shadow mapping and the accuracy of visibility ray tracing. A shadow refinement mask is derived from the result of the direct lighting pass and from a small number of shadow maps to identify the penumbral region of an area light source. This region is accurately rendered by ray tracing. For diffuse indirect illumination, we introduce radiosity photons to profit from the flexibility of a point-based sampling while maintaining the benefits of interpolation over scattered data approximation or density estimation. A sparse sampling of the scene is generated by particle tracing. An area is approximated for each point sample to compute the radiosity solution using a relaxation approach. The indirect illumination is interpolated between neighboring radiosity photons, stored in a multidimensional search tree. We compare different neighborhood search algorithms in terms of image quality and performance. Our method yields interactive frame rates and results consistent with path tracing reference solutions.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. Arvo, J.: Backward ray tracing. In: ACM SIGGRAPH 86 Course Notes—Developments in Ray Tracing, pp. 259–263 (1986)

  2. Cohen, M.F., Greenberg, D.P.: The hemi-cube: A radiosity solution for complex environments. In: SIGGRAPH ’85: Proceedings of the 12th Annual Conference on Computer Graphics and Interactive Techniques, pp. 31–40. ACM, New York (1985)

    Chapter  Google Scholar 

  3. Cohen, M.F., Chen, S.E., Wallace, J.R., Greenberg, D.P.: A progressive refinement approach to fast radiosity image generation. SIGGRAPH Comput. Graph. 22(4), 75–84 (1988)

    Article  Google Scholar 

  4. Cook, R.L., Porter, T., Carpenter, L.: Distributed ray tracing. SIGGRAPH Comput. Graph. 18(3), 137–145 (1984)

    Article  Google Scholar 

  5. Dobashi, Y., Yamamoto, T., Nishita, T.: Radiosity for point-sampled geometry. In: PG ’04: Proceedings of the Computer Graphics and Applications, 12th Pacific Conference, pp. 152–159. IEEE Computer Society, Los Alamitos (2004)

    Chapter  Google Scholar 

  6. Goral, C.M., Torrance, K.E., Greenberg, D.P., Battaile, B.: Modeling the interaction of light between diffuse surfaces. SIGGRAPH Comput. Graph. 18(3), 213–222 (1984)

    Article  Google Scholar 

  7. Hanrahan, P., Salzman, D., Aupperle, L.: A rapid hierarchical radiosity algorithm. In: SIGGRAPH ’91: Proceedings of the 18th Annual Conference on Computer Graphics and Interactive Techniques, pp. 197–206. ACM, New York (1991)

    Chapter  Google Scholar 

  8. Heckbert, P.S.: Adaptive radiosity textures for bidirectional ray tracing. SIGGRAPH Comput. Graph. 24(4), 145–154 (1990)

    Article  Google Scholar 

  9. Jensen, H.W.: Realistic Image Synthesis Using Photon Mapping. Peters, Natick (2001)

    MATH  Google Scholar 

  10. Jensen, H.W., Christensen, N.J.: Photon maps in bidirectional Monte Carlo ray tracing of complex objects. Comput. Graph. 19(2), 215–224 (1995)

    Article  Google Scholar 

  11. Kajiya, J.T.: The rendering equation. SIGGRAPH Comput. Graph. 20(4), 143–150 (1986)

    Article  Google Scholar 

  12. Lafortune, E.P., Willems, Y.D.: Bidirectional path tracing. In: Santo H.P. (ed.) Proceedings of Third International Conference on Computational Graphics and Visualization Techniques, Compugraphics ’93, pp. 145–153. Alvor, Portugal (1993)

  13. Lehtinen, J., Zwicker, M., Kontkanen, J., Turquin, E., Sillion, F., Aila, T.: Meshless finite elements for hierarchical global illumination. Technical Report TML-B7, Helsinki University of Technology, May (2007)

  14. Lehtinen, J., Zwicker, M., Turquin, E., Kontkanen, J., Durand, F., Sillion, F.X., Aila, T.: A meshless hierarchical representation for light transport. ACM Trans. Graph. 27(3), 1–9 (2008)

    Article  Google Scholar 

  15. McGuire, M., Luebke, D.: Hardware-accelerated global illumination by image-space photon mapping. In: HPG ’09: Proceedings of the Conference on High Performance Graphics 2009, pp. 77–89. ACM, New York (2009)

    Chapter  Google Scholar 

  16. Nichols, G., Shopf, J., Wyman, C.: Hierarchical image-space radiosity for interactive global illumination. Comput. Graph. Forum 28(4), 1141–1149 (2009)

    Article  Google Scholar 

  17. Pfister, H., Zwicker, M., van Baar, J., Gross, M.: Surfels: Surface elements as rendering primitives. In: SIGGRAPH ’00: Proceedings of the 27th Annual Conference on Computer Graphics and Interactive Techniques, pp. 335–342. ACM Press/Addison-Wesley, New York (2000)

    Chapter  Google Scholar 

  18. Pharr, M., Humphreys, G.: Physically Based Rendering: From Theory to Implementation. Morgan Kaufmann, New York (2004)

    Google Scholar 

  19. Ritschel, T., Grosch, T., Kim, M.H., Seidel, H.-P., Dachsbacher, C., Kautz, J.: Imperfect shadow maps for efficient computation of indirect illumination. ACM Trans. Graph. (Proc. of SIGGRAPH ASIA 2008) 27(5) (2008)

  20. Ritschel, T., Grosch, T., Seidel, H.-P.: Approximating dynamic global illumination in image space. In: I3D ’09: Proceedings of the 2009 Symposium on Interactive 3D Graphics and Games, pp. 75–82. ACM, New York (2009)

    Chapter  Google Scholar 

  21. Stamminger, M., Scheel, A., Seidel, H.-P.: Hierarchical radiosity with global refinement. In: Girod, B., Greiner, G., Niemann, H., Seidel, H.-P. (eds.) Proceedings of Vision, Modeling, and Visualization (VMV-00), pp. 263–270. Akademische Verlagsgesellschaft Aka, Saarbrücken (2000)

    Google Scholar 

  22. Veach, E.: Robust Monte Carlo methods for light transport simulation. Ph.D. thesis. Stanford University (1998)

  23. Wang, R., Wang, R., Zhou, K., Pan, M., Bao, H.: An efficient GPU-based approach for interactive global illumination. ACM Trans. Graph. 28(3), 1–8 (2009)

    Google Scholar 

  24. Ward, G.J., Rubinstein, F.M., Clear, R.D.: A ray tracing solution for diffuse interreflection. In: SIGGRAPH ’88: Proceedings of the 15th Annual Conference on Computer Graphics and Interactive Techniques, pp. 85–92. ACM, New York (1988)

    Chapter  Google Scholar 

  25. Whitted, T.: An improved illumination model for shaded display. SIGGRAPH Comput. Graph. 13(2), 14 (1979)

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. University of Koblenz, Universitätsstr. 1, 56070, Koblenz, Germany

    Erik Knauer, Jakob Bärz & Stefan Müller

Authors
  1. Erik Knauer
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Jakob Bärz
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Stefan Müller
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Jakob Bärz.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Knauer, E., Bärz, J. & Müller, S. A hybrid approach to interactive global illumination and soft shadows. Vis Comput 26, 565–574 (2010). https://doi.org/10.1007/s00371-010-0437-y

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00371-010-0437-y

Keywords

Search

Navigation