Master 2010-2011
Real-time Animation and Rendering of Ocean Whitecaps

Advisor

Eric Bruneton
LJK/EVASION

Context

The research work about landscape modeling and real-time high quality rendering at Evasion.

Description

Realistic animation and rendering of the ocean is an important aspect for simulators, movies and video games. There are many algorithms for modelling, animating and rendering it. Synthesizing the surface has been done by summing wave trains [Fournier 86, Premoze 00, Hinsinger 02] or by using a FFT to convert a frequency spectrum to a surface [Tessendorf 05]. Rendering with adaptive geometric resolution has been done with a projected grid from screen [Hinsinger 02, Bruneton 10], with a dynamic quadtree, or with deferred shading [Toman 09]. However, most authors concentrate on the animation and rendering of waves, and often ignore foam and whitecaps, which appear for wind speeds above 25 km/h. Those that propose methods to handle foam and whitecaps either use very simple models based on the wave height [Chui 06, Darles 06, Li 08, Toman 09] or distortion [Tessendorf 05], or use complex physical simulations that do not scale for very large scenes [Lei 08, Thurey 07a]. Also these authors never consider how foam and whitecaps influence the appearance of the ocean at large distances (e.g. near the horizon, or in aerial views).

In this context we propose to study the real-time animation and rendering of ocean foam and whitecaps, for all viewpoints from sea level to aerial views, and for very large scenes. The first step is to study the physics literature on this topic (in addition to the Computer Graphics literature), in order to improve the simple models currently used in Computer Graphics to decide where to generate foam, and how to animate and render it. Indeed, physicists haved measured the amount of whitecaps depending on sea state [Huang 86], the evolution of whitecaps and their reflectance [Koepke 84], etc. The second step is to propose a scalable rendering and animation method based on these models, with a particular emphasis on the influence of whitecaps on the appearance of the ocean at large distances. The last step is to evaluate the proposed method by comparing its results with reference images.

References

[Bruneton 10] Real-time Realistic Ocean Lighting using Seamless Transitions from Geometry to BRDF
Bruneton E., Neyret F., Holzschuch N., Eurographics, 2010.

[Chiu 06] GPU-based Ocean Rendering
Chiu Y-F., Chang C-F., IEEE International Conference on Multimedia and Expo, 2006.

[Darles 06] Accelerating and enhancing rendering of realistic ocean scenes
Darles E., Crespin B., Ghazanfarpour D., WSCG, 2007.

[Fournier 86] A simple model of ocean waves
Fournier A., Reeves W. T., SIGGRAPH, 1986.

[Hinsinger 02] Interactive animation of ocean waves
Hinsinger D., Neyret F., Cani M.-P., SCA, 2002.

[Huang 86] An Analytical Model for Oceanic Whitecap Coverage
Huang N. E., Bliven L. F., Long S. R., Tung C-C., Journal of Physical Oceanography, 1986.

[Koepke 84] Effective reflectance of oceanic whitecaps
Koepke P., Applied Optics, 1984.

[Lei 08] A Particle-Guided Method for Animating Splashing Stream Water in Real Time
Lei S-I. E., Chang C-F., Pacific Graphics Posters, 2008.

[Li 08] Simulation of Shallow-Water Waves in Coastal Region for Marine Simulator
Li Y., Jin Y., Yin Y., Shen H., International Conference on Virtual-Reality Continuum and Its Applications in Industry, 2008.

[Parenthoen 04] Animation phénoménologique de la mer - une approche énactive
Parenthoen M., These de doctorat, 2004.

[Premoze 00] Rendering natural waters
Premoze S., Ashikhmin M., Pacific Graphics, 2000.

[Tessendorf 05] Simulating Ocean Water
Tessendorf J., SIGRRAPH Course Notes, 2005.

[Thurey 07a] Real-time simulations of bubbles and foam within a shallow water framework
Thurey N., Sadlo F., Schirm S., Muller-Fisher M., Gross M., SCA, 2007.

[Thurey 07b] Real-time BreakingWaves for Shallow Water Simulations
Thurey N., Muller-Fisher M., Schirm S., Gross M., Pacifics Graphics, 2007.

[Toman 09] Rendering Water as a Post-process Effect
Toman W., Gamedev, 2009.