Skip to main content
Log in

Separable soft shadow mapping

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

Abstract

We propose an efficient technique for rendering visually plausible real-time soft shadows in screen space. First, we propose a novel blocker estimation technique based on a separable filter. Second, our technique performs a separable Gaussian blur in screen space over the hard shadows produced by the standard shadow mapping technique. Although blurring the hard shadows with a separable filter was done before in the literature using bilateral filtering, we use an alternative approach that minimizes artifacts. Since separated calculation is not possible for all cases, we provide data reutilization criteria based on two user-defined error thresholds called \(\alpha \) and \(\beta \). As a consequence of using separable approaches for both stages of the light visibility estimation, our technique is able to improve rendering performance, especially when high-resolution shadow maps and filtering kernels are used.

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

Access this article

Subscribe and save

Springer+ Basic
EUR 32.99 /Month
  • Get 10 units per month
  • Download Article/Chapter or Ebook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime
Subscribe now

Buy Now

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

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13

Similar content being viewed by others

References

  1. Annen, T., Dong, Z., Mertens, T., Bekaert, P., Seidel, H.P., Kautz, J.: Real-time, all-frequency shadows in dynamic scenes. ACM Trans. Graph. 27(3), 1–8 (2008)

    Article  Google Scholar 

  2. Annen, T., Mertens, T., Bekaert, P., Seidel, H.P., Kautz, J.: Convolution shadow maps. In: Rendering Techniques 2007: Eurographics Symposium on Rendering, pp. 51–60. Eurographics, Grenoble, France (2007)

  3. Annen, T., Mertens, T., Seidel, H.P., Flerackers, E., Kautz, J.: Exponential shadow maps. In: GI ’08: Proceedings of graphics interface 2008, pp. 155–161. Canadian Information Processing Society, Toronto, Ontario, Canada (2008)

  4. Atty, L., Holzschuch, N., Lapierre, M., Hasenfratz, J.M., Sillion, F.X., Hansen, C.: Soft shadow maps: efficient sampling of light source visibility. Comput. Graph. Forum 25(4), 725–741 (2006). doi:10.1111/j.1467-8659.2006.00995.x. http://hal.inria.fr/inria-00281374

  5. Baoguang, Y., Feng, J., Guennebaud, G., Liu, X.: Packet-based hierarchal soft shadow mapping. Comput. Graph. Forum 28(4), 1121–1130 (2009). http://hal.inria.fr/inria-00390541

  6. Cai, X.H., Jia, Y.T., Wang, X., Hu, S.M., Martin, R.R.: Rendering soft shadows using multilayered shadow fins. Comput. Graph. Forum 25(1), 15–28 (2006). http://dblp.uni-trier.de/db/journals/cgf/cgf25.html

  7. Chan, E., Durand, F.: Rendering fake soft shadows with smoothies. In: Proceedings of the Eurographics Symposium on Rendering, pp. 208–218. Eurographics Association (2003)

  8. Doidge, I., Jones, M.: Probabilistic illumination-aware filtering for monte carlo rendering. Vis. Comput. 29(6–8), 707–716 (2013). doi:10.1007/s00371-013-0807-3

  9. Dong, Z., Yang, B.: Variance soft shadow mapping. In: Proceedings of the 2010 ACM SIGGRAPH Symposium on Interactive 3D Graphics and Games, I3D ’10, pp. 18:1–18:1. ACM, New York, NY, USA (2010). doi:10.1145/1730804.1730990

  10. Donnelly, W., Lauritzen, A.: Variance shadow maps. In: Proceedings of the 2006 Symposium on Interactive 3D Graphics and Games, I3D ’06, pp. 161–165. ACM, New York, NY, USA (2006). doi:10.1145/1111411.1111440

  11. Eisemann, E., Schwarz, M., Assarsson, U., Wimmer, M.: Real-Time Shadows. A.K. Peters, Natick, Massachusetts, USA (2011). http://www.cg.tuwien.ac.at/research/publications/2011/EISEMANN-2011-RTS/

  12. Fernando, R.: Percentage-closer soft shadows. In: ACM SIGGRAPH 2005 Sketches, SIGGRAPH ’05. ACM, New York, NY, USA (2005). doi:10.1145/1187112.1187153

  13. Guennebaud, G., Barthe, L., Paulin, M.: Realtime soft shadow mapping by backprojection. In: Eurographics Symposium on Rendering, pp. 227–234 (2006)

  14. Guennebaud, G., Barthe, L., Paulin, M.: High-quality adaptive soft shadow mapping. In: Eurographics 2007 Proceedings on Computer Graphics Forum, vol. 26(3), pp. 525–534 (2007)

  15. Gumbau, J., Chover, M., Sbert, M.: Screen space soft shadows. In: Engel, W. (ed.) GPU Pro, pp. 477–491. A.K. Peters/CRC Press, Natick, Massachusetts, USA (2010) doi:10.1201/b10648-36

  16. Hasenfratz, J.M., Lapierre, M., Holzschuch, N., Sillion, F.X.: A survey of real-time soft shadows algorithms. Comput. Forum 22(4), 753–774 (2003). doi:10.1111/j.1467-8659.2003.00722.x

    Article  Google Scholar 

  17. MohammadBagher, M., Kautz, J., Holzschuch, N., Soler, C.: Screen-space percentage-closer soft shadows. In: ACM SIGGRAPH 2010 Posters, SIGGRAPH ’10, pp. 133:1–133:1. ACM, New York, NY, USA (2010). doi:10.1145/1836845.1836987

  18. Reeves, W.T., Salesin, D.H., Cook, R.L.: Rendering antialiased shadows with depth maps. SIGGRAPH Comput. Graph. 21(4), 283–291 (1987). doi:10.1145/37402.37435

  19. Schwarz, M., Stamminger, M.: Bitmask soft shadows. Comput. Graph. Forum 26(3), 515–524 (2007)

  20. Schwärzler, M., Luksch, C., Scherzer, D., Wimmer, M.: Fast percentage closer soft shadows using temporal coherence. In: Proceedings of the ACM SIGGRAPH symposium on interactive 3D graphics and games, I3D ’13, pp. 79–86. ACM, New York, NY, USA (2013). doi:10.1145/2448196.2448209

  21. Shen, L., Feng, J., Yang, B.: Exponential soft shadow mapping. In: Eurographics Symposium on Rendering, vol. 32. The Eurographics Association and Wiley (2013). doi:10.1111/cgf.12156

  22. Sintorn, E., Kämpe, V., Olsson, O., Assarsson, U.: Compact precomputed voxelized shadows. ACM Trans. Graph. 33(4), 150:1–150:8 (2014). doi:10.1145/2601097.2601221

  23. Williams, L.: Casting curved shadows on curved surfaces. In: Proceedings of the 5th Annual Conference on Computer Graphics and Interactive Techniques, SIGGRAPH ’78, pp. 270–274. ACM, New York, NY, USA (1978). doi:10.1145/800248.807402

  24. Zheng, Z., Saito, S.: Screen space anisotropic blurred soft shadows. In: ACM SIGGRAPH 2011 Posters, SIGGRAPH ’11, pp. 75:1–75:1. ACM, New York, NY, USA (2011). doi:10.1145/2037715.2037799

Download references

Acknowledgments

This work has been supported by the Spanish Ministry of Education and Science (TIN2013-47276-C6-6-R), the Valencian Community (PROMETEOII/2014/062) and the University Jaime I (P1\(\cdot \)1B2014-37).

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Jesús Gumbau.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Buades, J.M., Gumbau, J. & Chover, M. Separable soft shadow mapping. Vis Comput 32, 167–178 (2016). https://doi.org/10.1007/s00371-015-1062-6

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00371-015-1062-6

Keywords

Navigation