Steven Worley has source code available for his cellular basis function. See www.texturingandmodeling.com
Is this something that could be incorporated as another function to call in procedural materials, similar to fnoise and others?
The copyright (see below) would seem to allow for use of the code in a pretty open manner.
-Jack de Valpine
/* Copyright 1994, 2002 by Steven Worley
This software may be modified and redistributed without restriction
provided this comment header remains intact in the source code.
This code is provided with no warrantee, express or implied, for
A detailed description and application examples can be found in the
1996 SIGGRAPH paper "A Cellular Texture Basis Function" and
especially in the 2002 book "Texturing and Modeling, a Procedural
Approach, 3rd edition." There is also extra information on the web
site http://www.worley.com/cellular.html .
If you do find interesting uses for this tool, and especially if
you enhance it, please drop me an email at email@example.com. */
An implementation of the key cellular texturing basis
function. This function is hardwired to return an average F_1 value
of 1.0. It returns the <n> most closest feature point distances
F_1, F_2, .. F_n the vector delta to those points, and a 32 bit
seed for each of the feature points. This function is not
difficult to extend to compute alternative information such as
higher order F values, to use the Manhattan distance metric, or
other fun perversions.
<at> The input sample location. <max_order> Smaller values compute faster. < 5, read the book to extend it.
<F> The output values of F_1, F_2, ..F[n] in F, F, F[n-1]
<delta> The output vector difference between the sample point and the n-th
closest feature point. Thus, the feature point's location is the
hit point minus this value. The DERIVATIVE of F is the unit
normalized version of this vector.
<ID> The output 32 bit ID number which labels the feature point. This
is useful for domain partitions, especially for coloring flagstone
This implementation is tuned for speed in a way that any order > 5
will likely have discontinuous artifacts in its computation of F5+.
This can be fixed by increasing the internal points-per-cube
density in the source code, at the expense of slower
computation. The book lists the details of this tuning. */
# John E. de Valpine
# visarc incorporated
# channeling technology for superior design and construction