X-M1 & M2R project :
« Playing with Fourier spectrum 
for real-time ocean explorer and texture generation »

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Fabrice NEYRET   - Maverick team, LJK, at INRIA-Montbonnot (Grenoble)


The Fourier transform helps generating realistic and rich phenomenons such as material appearance or wavy ocean surfaces: Physicists describe oceanographic wave statistics with power spectrum and wave motion with dispersion law. In Computer Graphics this has been used to synthesize realistic ocean surface in movies, and nowadays it can even run in real-time on graphics card using GLSL shaders, e.g. for application in games and simulators. Stochastic textures can also be analyzed and synthesized with this tool.

Description of the subject

Fourier transform is thus a very powerful tool, but it comes with annoying intrinsic limitations: it generates only periodic worlds, statistically homogeneous along space, and one cannot easily evolve the look along time as well. Moreover, in real-time walk-through applications the world is vast, and detailed if seen from nearby, so we can’t explicitly generate everything once. Scalability and on-the-fly adaptiveness is thus required: we need to be able to rescale dynamically the span and precision while preserving seamless space and time continuity (i.e., without introducing horrible visual artifacts). Similarly, image textures to be analyzed must be periodic, which is not a convenient constraint.
The main purpose of this subject is to explore various ways to overcome these limitations, making Fourier approaches more pliable.