Abstract
Shadow maps sample scene visibility in the light source space and offer an efficient solution to generate hard shadows. However, they suffer from aliasing artifacts because of discretization errors, inadequate resolution and projection distortion. In this paper, we propose the shadow geometry map method, where a shadow depth map is augmented by storing geometry information about scenes. This leads to a new shadowrendering algorithm that combines a supersampling filter, a geometry-aware reconstruction kernel and an irregular sampling filter. Our method produces high quality alias-free and subpixel supersampling shadow rendering and retains the simplicity and the efficiency of shadow maps. We show that the algorithm pipeline is efficiently parallelized using current programmable graphics hardware and that our method is capable of generating high quality hard shadows.
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References
Crow F C. Shadow algorithms for computer graphics. In: Proceedings of ACM SIGGRAPH. San Jose: ACM, 1977. 242–248
Whitted T. An improved illumination model for shaded display. Commun ACM, 1980, 23: 343–349
Williams L. Casting curved shadows on curved surfaces. Comput Graph, 1978, 12: 270–274
Reeves W T, Salesin D, Cook R L. Rendering antialiased shadows with depth maps. In: Proceedings of ACM SIGGRAPH. Anaheim: ACM, 1987. 283–291
Fernando R, Fernandez S, Bala K. Adaptive shadow maps. In: Proceedings of ACM SIGGRAPH. Los Angeles: ACM, 2001. 387–390
Stamminger M, Drettakis G. Perspective shadow maps. ACM Trans Graphic, 2002, 21: 557–562
Chung H, Gortler S J. A lixel for every pixel. In: Keller A, Jensen H W, eds. Proceedings of Eurographics Symposium on Rendering. Norkoping: Eurographics Association, 2004. 167–172
Wimmer M, Scherzer D, Purgathofer W. Light space perspective shadow maps. In: Keller A, Jensen H W, eds. Proceedings of the Eurographics Symposium on Rendering. Norkoping: Eurographics Association, 2004. 143–151
Lloyd B, Tuft D, Yoon S, et al. Warping and partitioning for low error shadow maps. In: Akenine-Muller T, Heidrich W, eds. Proceedings of the Eurographics Symposium on Rendering. Nicosia: Eurographics Association, 2006. 215–226
Lefohn A E, Sengupta S, Owens J D. Resolution-matched shadow maps. ACM Trans Graphic, 2007, 26: 1–17
Lloyd B, Govindaraju N, Quammen C, et al. Logarithmic perspective shadow maps. ACM Trans Graphic, 2008, 27: 1–106
Aila T, Laine S. Alias-free shadow maps. J Graphic Tool, 2007, 12: 47–59
Johnson G, Mark W, Burns C. The irregular Z-Buffer and its Application to Shadow Mapping. Technical Report TR-04-09. Austin: University of Texas, 2004
Johnson G S, Lee J, Burns C A, et al. The irregular Z-buffer: hardware acceleration for irregular data structures. ACM Trans Graphic, 2005, 24: 1462–1482
Sintorn E, Eisemann E, Assarsson U. Sample based visibility for soft shadows using alias-free shadow maps. Comput Graph Forum, 2008, 27: 1285–1292
Johnson G S, Hunt W A, Hux A, et al. Soft irregular shadow mapping: fast, high-quality, and robust soft shadows. In: I3D’ 09: Proceedings of the 2009 Symposium on Interactive 3D Graphics and Games. Boston: ACM, 2009. 57–66
Pan M H, Wang R, Chen W F. Fast, sub-pixel antialiased shadow maps. Comput Graph Forum, 2009, 12: 1–34
Donnelly W, Lauritzen A. Variance shadow maps. In: I3D’ 06: Proceedings of the 2006 Symposium on Interactive 3D Graphics and Games. Redwood City: ACM, 2006. 161–165
Thomas A, Tom M, Hans-Peter S, et al. Convolution shadow maps. In: Kautz J, Pattanaik S N, eds. Rendering Techniques 2007: Eurographics Symposium on Rendering. Grenoble: Eurographics Association, 2007. 51–60
Martin T, Tan T S. Anti-aliasing and continuity with trapezoidal shadow maps. In: Keller A, Jensen H W, eds. Rendering Techniques 2004: Proceedings of Eurographics Symposium on Rendering. Norkoping: Eurographics Association, 2004. 51–60
Lloyd B, Govindaraju N K, Molnar S E, et al. Practical logarithmic rasterization for low-error shadow maps. In: Stephen N, ed. Proceedings of ACM SIGGRAPH/EUROGRAPHICS Symposium on Graphics Hardware. Switzerland: Eurographics Association, 2007. 17–24
Zhang F, Sun H Q, Xu L L, et al. Parallel-split shadow maps for large-scale virtual environments. In: Sun H Q, ed. Proceedings of ACM International Conference on Virtual Reality Continuum and its Applications. New York: ACM, 2006. 311–318
Sen P, Cammarano M, Hanrahan P. Shadow silhouette maps. ACM Trans Graphic, 2003, 22: 521–526
Grand S L. Broad-phase collision detection with CUDA. In: Nguyen H, ed. GPU Gems 3. Addison-Wesley, 2007. 697–721
Nickolls J, Buck I, Garland M, et al. Scalable parallel programming with CUDA. In: ACM SIGGRAPH 2008 Classes. Los Angeles: ACM, 2008. 1–14
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Wang, R., Wu, Y., Pan, M. et al. Shadow geometry maps for alias-free shadows. Sci. China Inf. Sci. 56, 1–12 (2013). https://doi.org/10.1007/s11432-012-4696-2
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DOI: https://doi.org/10.1007/s11432-012-4696-2