“A practical analytic single scattering model for real time rendering” by Sun, Ramamoorthi, Narasimhan and Nayar

We consider real-time rendering of scenes in participating media, capturing the effects of light scattering in fog, mist and haze. While a number of sophisticated approaches based on Monte Carlo and finite element simulation have been developed, those methods do not work at interactive rates. The most common real-time methods are essentially simple variants of the OpenGL fog model. While easy to use and specify, that model excludes many important qualitative effects like glows around light sources, the impact of volumetric scattering on the appearance of surfaces such as the diffusing of glossy highlights, and the appearance under complex lighting such as environment maps. In this paper, we present an alternative physically based approach that captures these effects while maintaining real time performance and the ease-of-use of the OpenGL fog model. Our method is based on an explicit analytic integration of the single scattering light transport equations for an isotropic point light source in a homogeneous participating medium. We can implement the model in modern programmable graphics hardware using a few small numerical lookup tables stored as texture maps. Our model can also be easily adapted to generate the appearances of materials with arbitrary BRDFs, environment map lighting, and precomputed radiance transfer methods, in the presence of participating media. Hence, our techniques can be widely used in real-time rendering.

1. Ashikhmin, M., and Shirley, P. 2000. An anisotropic phong model. Journal of Graphics Tools 5, 2, 25–32. Google ScholarDigital Library
2. Basri, R., and Jacobs, D. W. 2003. Lambertian reflectance and linear subspaces. IEEE Trans. Pattern Anal. Mach. Intell. 25, 2, 218–233. Google ScholarDigital Library
3. Biri, V., Michelin, S., and Arques, D. 2004. Real-time single scattering with shadows. In In review http://igm.univ-mlv.fr/~biri/indexCA_en.html.Google Scholar
4. Blinn, J. 1982. Light reflection functions for simulation of clouds and dusty surfaces. In Computer Graphics(Proceedings of ACM SIGGRAPH 82), ACM, 21–29. Google ScholarDigital Library
5. Chandrasekhar, S. 1960. Radiative Transfer. Oxford Univ. Press.Google Scholar
6. Debevec, P. 1998. Rendering synthetic objects into real scenes: bridging traditional and image-based graphics with global illumination and high dynamic range photography. In Proceedings of ACM SIGGRAPH 1998, ACM Press/ACM SIGGRAPH, New York. E. Fiume, Ed., Computer Graphics Proceedings, Annual Conference Series, ACM, 189–198. Google ScholarDigital Library
7. Dobashi, Y., Yamamoto, T., and Nishita, T. 2002. Interactive rendering of atmospheric scattering effects using graphics hardware. In Graphics Hardware Workshop 02, 99–109. Google ScholarDigital Library
8. Hanrahan, P., and Krueger, W. 1993. Reflection from layered surfaces due to subsurface scattering. In Proceedings of ACM SIGGRAPH 1993, ACM Press/ACM SIGGRAPH, New York. E. Fiume, Ed., Computer Graphics Proceedings, Annual Conference Series, ACM, 165–174. Google ScholarDigital Library
9. Harris, M., and Lastra, A. 2001. Real-time cloud rendering. In Eurographics 2001, 76–84.Google Scholar
10. Hoffman, N., and Preetham, A. J. 2003. Real-time light-atmosphere interactions for outdoor scenes. Graphics programming methods, 337–352. Google ScholarDigital Library
11. Jensen, H., Marschner, S., Levoy, M., and Hanrahan, P. 2001. A practical model for subsurface light transport. In Proceedings of ACM SIGGRAPH 2001, ACM Press/ACM SIGGRAPH, New York, E. Fiume, Ed., Computer Graphics Proceedings, Annual Conference Series, ACM, 511–518. Google ScholarDigital Library
12. Jensen, H. W. 2001. Realistic Image Synthesis Using Photon Mapping. AK Peters. Google ScholarDigital Library
13. Kajiya. J., and Herzen, B. 1984. Ray tracing volume densities. In Proceedings of ACM SIGGRAPH 1984, ACM Press/ACM SIGGRAPH, New York. E. Fiume, Ed., Computer Graphics Proceedings, Annual Conference Series, ACM, 165–174. Google ScholarDigital Library
14. Koschmeider, H. 1924. Theorie der horizontalen sichtweite. Beitr. Phys. freien Atm., 12.Google Scholar
15. Liu, X., Sloan, P.-P. J., Shum, H.-Y., and Snyder, J. 2004. All-frequency precomputed radiance transfer for glossy objects. In EuroGraphics Symposium on Rendering 04, 337–344. Google ScholarDigital Library
16. Matusik, W., Pfister, H., Brand, M., and McMillan, L. 2003. A data-driven reflectance model. ACM Transactions on Graphics 22, 3, 759–769. Google ScholarDigital Library
17. Max., N. L. 1986. Atmospheric illumination and shadows. In Computer Graphics(Proceedings of ACM SIGGRAPH 86), ACM, 117–124. Google ScholarDigital Library
18. Max, N. 1994. Efficient light propagation for multiple anisotropic volume scattering. In Eurographics Rendering Workshop 94, 87–104.Google Scholar
19. Nakamae, E., Kaneda, K., Okamoto, T., and Nishita, T. 1990. A lighting model aiming at drive simulators. In Computer Graphics(Proceedings of ACM SIGGRAPH 90), 395–404. Google ScholarDigital Library
20. Narasimhan, S., and Nayar, S. 2002. Vision and the atmosphere. IJCV 48, 3 (August), 233–254. Google ScholarDigital Library
21. Narasimhan, S., and Nayar, S. 2003. Shedding light on the weather. In CVPR 03, 665–672. Google ScholarDigital Library
22. Nishita, T., and Nakamae, E. 1987. A shading model for atmospheric scattering considering luminous intensity distribution of light sources. In Computer Graphics(Proceedings of ACM SIGGRAPH 1987), ACM, 303–310. Google ScholarDigital Library
23. Pattanaik, S., and Mudur, S. 1993. Computation of global illumination in a participating medium by monte carlo simulation. Journal of Visualization and Computer Animation 4, 3, 133–152.Google ScholarCross Ref
24. Preetham, A. J., Shirley, P., and Smits, B. 1999. A practical analytic model for daylight. In Proceedings of ACM SIGGRAPH 1999, ACM Press/ACM SIGGRAPH, New York. E. Fiume, Ed., Computer Graphics Proceedings, Annual Conference Series, ACM, 91–100. Google ScholarDigital Library
25. Premoze, S., Ashikhmin, M., Tesendorf, J., Ramamoorthi, R., and Nayar, S. 2004. Practical rendering of multiple scattering effects in participating media. In EuroGraphics Symposium on Rendering 04, 363–374. Google ScholarDigital Library
26. Ramamoorthi, R., and Hanrahan, P. 2001. A signal-processing framework for inverse rendering. In Proceedings of ACM SIGGRAPH 2001, ACM Press/ACM SIGGRAPH, New York. E. Fiume, Ed., Computer Graphics Proceedings, Annual Conference Series, ACM, 117–128. Google ScholarDigital Library
27. Ramamoorthi, R., and Hanrahan, P. 2002. Frequency space environment map rendering. ACM Transactions on Graphics (SIGGRAPH 02) 21, 3, 517–526. Google ScholarDigital Library
28. Riley, K., Ebert, D., Kraus, M., Tessendorf, J., and Hansen, C. 2004. Efficient rendering of atmospheric phenomena. In EuroGraphics Symposium on Rendering 2004, 375–386. Google ScholarDigital Library
29. Rushmeier, H., and Torrance, K. 1987. The zonal method for calculating light intensities in the presence of a participating medium. In Proceedings of ACM SIGGRAPH 1987, ACM Press/ACM SIGGRAPH, New York. E. Fiume, Ed., Computer Graphics Proceedings, ACM, 293–302. Google ScholarDigital Library
30. Sakas, G. 1990. Fast rendering of arbitrary distributed volume densities. In Eurographics 90, 519–530.Google Scholar
31. Sloan, P.-P., Kautz, J., and Snyder, J. 2002. Precomputed radiance transfer for real-time rendering in dynamic, low-frequency lighting environments. ACM Transactions on Graphics 21, 3, 527–536. Google ScholarDigital Library
32. Stam, J. 1995. Multiple scattering as a diffusion process. In Eurographics Rendering Workshop 95, 41–50.Google ScholarCross Ref
33. Wang, R., Tran, J., and Luebke, D. 2004. All-frequency relighting of non-diffuse objects using separable BRDF approximation. In EuroGraphics Symposium on Rendering 2004, 345–354. Google ScholarDigital Library