ABSTRACT
Shadow aliasing due to limited storage precision has been plaguing discrete shadowing algorithms for decades. We present a simple method to eliminate false self-shadowing through adaptive depth bias. Unlike existing methods which simply set the weight of the bias based on surface slope or utilize the second nearest surface, we evaluate the bound of bias for each fragment and compute the optimal bias within the bound. Our method introduces small overhead, preserves more shadow details than widely used constant bias and slope scale bias and works for common 2D shadow maps as well as 3D binary shadow volumes.
- Aila, T., and Laine, S. 2004. Alias-free shadow maps. In Proceedings of Eurographics Symposium on Rendering, vol. 2004, 161--166. Google ScholarDigital Library
- Arvo, J. 2007. Alias-free shadow maps using graphics hardware. Journal of Graphics, GPU, and Game Tools 12, 1, 47--59.Google ScholarCross Ref
- Brabec, S., Annen, T., and Seidel, H.-P. 2002. Shadow mapping for hemispherical and omnidirectional light sources. In Advances in Modelling, Animation and Rendering. Springer, 397--407.Google Scholar
- Dai, Q., Yang, B., and Feng, J. 2008. Reconstructable geometry shadow maps. In Proceedings of the 2008 symposium on Interactive 3D graphics and games, ACM, 4. Google ScholarDigital Library
- Dietrich, S. 2001. Practical priority buffer shadows. Game Programming Gems II, 482.Google Scholar
- Eisemann, E., Schwarz, M., Assarsson, U., and Wimmer, M. 2011. Real-time shadows. AK Peters, Ltd. Google ScholarDigital Library
- Fernando, R., Fernandez, S., Bala, K., and Greenberg, D. P. 2001. Adaptive shadow maps. In Proceedings of the 28th annual conference on Computer graphics and interactive techniques, ACM, 387--390. Google ScholarDigital Library
- Gautron, P., Marvie, J., and Briand, G., 2013. Method for generating shadows in an image, Jan. 23. EP Patent 2,411,967.Google Scholar
- Gregory S. Johnson, W. R. M., and Burns, C. A. March 2004. The irregular z-buffer and its application to shadow mapping. Tech. rep., University of Texas Department of Computer Sciences Technical Report.Google Scholar
- King, G. 2004. Shadow mapping algorithms. GPU Jackpot presentation, 354--355.Google Scholar
- Scherzer, D., Wimmer, M., and Purgathofer, W. 2011. A survey of real-time hard shadow mapping methods. In Computer Graphics Forum, vol. 30, Wiley Online Library, 169--186.Google Scholar
- Sintorn, E., Eisemann, E., and Assarsson, U. 2008. Sample based visibility for soft shadows using alias-free shadow maps. Computer Graphics Forum (Proceedings of the Eurographics Symposium on Rendering 2008) 27, 4, 1285--1292. Google ScholarDigital Library
- Stamminger, M., and Drettakis, G. 2002. Perspective shadow maps. In ACM Transactions on Graphics (TOG), vol. 21, ACM, 557--562. Google ScholarDigital Library
- Tadamura, K., Qin, X., Jiao, G., and Nakamae, E. 2001. Rendering optimal solar shadows with plural sunlight depth buffers. The Visual Computer 17, 2, 76--90.Google ScholarCross Ref
- Wang, Y., and Molnar, S. 1994. Second-depth shadow mapping. UNC-CS Technical Report TR94-019. Google ScholarDigital Library
- Weiskopf, D., and Ertl, T. 2003. Shadow mapping based on dual depth layers. In Proceedings of Eurographics, vol. 3, 53--60.Google Scholar
- Williams, L. 1978. Casting curved shadows on curved surfaces. In ACM SIGGRAPH Computer Graphics, vol. 12, ACM, 270--274. Google ScholarDigital Library
- Wimmer, M., Scherzer, D., and Purgathofer, W. 2004. Light space perspective shadow maps. In Proceedings of the Fifteenth Eurographics conference on Rendering Techniques, Eurographics Association, 143--151. Google ScholarDigital Library
- Woo, A., Poulin, P., and Fournier, A. 1990. A survey of shadow algorithms. Computer Graphics and Applications, IEEE 10, 6, 13--32. Google ScholarDigital Library
- Woo, A. 1992. The shadow depth map revisited. In Graphics Gems III, Academic Press Professional, Inc., 338--342. Google ScholarDigital Library
- Wyman, C., and Dai, Z. 2013. Imperfect voxelized shadow volumes. In ACM SIGGRAPH 2013 Talks, ACM, New York, NY, USA, SIGGRAPH '13, 18:1--18:1. Google ScholarDigital Library
- Wyman, C. 2011. Voxelized shadow volumes. In Proceedings of the ACM SIGGRAPH Symposium on High Performance Graphics, ACM, 33--40. Google ScholarDigital Library
Index Terms
- Adaptive depth bias for shadow maps
Recommendations
Soft shadows from extended light sources with penumbra deep shadow maps
GI '05: Proceedings of Graphics Interface 2005This paper presents a new method of precomputing high-quality soft shadows that can be cast on a static scene as well as on dynamic objects added to that scene. The method efficiently merges the visibility computed from many shadow maps into a penumbra ...
Fitted virtual shadow maps
GI '07: Proceedings of Graphics Interface 2007Too little shadow map resolution and resulting undersampling artifacts, perspective and projection aliasing, have long been a fundamental problem of shadowing scenes with shadow mapping.
We present a new smart, real-time shadow mapping algorithm that ...
Shadow silhouette maps
The most popular techniques for interactive rendering of hard shadows are shadow maps and shadow volumes. Shadow maps work well in regions that are completely in light or in shadow but result in objectionable artifacts near shadow boundaries. In ...
Comments