Worley noise
Worley noise is a noise function introduced by Steven Worley in 1996. In computer graphics it is used to create procedural textures,[1] i.e. textures that are created automatically with arbitrary precision and do not have to be drawn by hand. Worley noise comes close to simulating textures of stone, water, or biological cells.
Example picture generated with Worley noise's basic algorithm. Tweaking of seed points and colors would be necessary to make this look like stone.
Basic algorithm
The basic idea is to take random points in space (2- or 3-dimensional) and then for every location in space take the distances dn to the nth-closest point (e.g. the second-closest point) and use combinations of those to control color information ( note that dn+1 > dn). More precisely:
- Randomly distribute feature points in space organised as grid cells. In practice this is done on the fly without storage (as a procedural noise). The original method considered a variable number of seed points per cell so as to mimic a Poisson distribution, but many implementations just put one.
- At run time, extract the distances dn from the given location to the nth-closest seed point. This can be done efficiently by visiting the current cell plus its neighbors.
- Noise W(x) is formally the vector of distances, plus possibly the corresponding seed ids, user-combined so as to produce a color.
See also
References
- Patrick Cozzi; Christophe Riccio (2012). OpenGL Insights. CRC Press. pp. 113–115. ISBN 978-1-4398-9376-0.
Further reading
- Worley, Steven (1996). A cellular texture basis function (PDF). Proceedings of the 23rd annual conference on computer graphics and interactive techniques. acm.org. pp. 291–294. ISBN 0-89791-746-4.
- David S. Ebert; F. Kenton Musgrave; Darwyn Peachey; Ken Perlin; Steve Worley (2002). Texturing and Modeling: A Procedural Approach. Morgan Kaufmann. pp. 135–155. ISBN 978-1-55860-848-1.
External links
- Detailed description on how to implement cell noise
- A version with the color plates appended at the end
| Characteristics |    | |
|---|---|---|
| Iterated function system | ||
| Strange attractor | ||
| L-system | ||
| Escape-time fractals | ||
| Rendering techniques | ||
| Random fractals | ||
| People | ||
| Other | ||
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