POV-Ray : Newsgroups : povray.unofficial.patches : Function problems in MegaPov : Re: Function problems in MegaPov Server Time
1 Sep 2024 22:13:34 EDT (-0400)
  Re: Function problems in MegaPov  
From: Greg M  Johnson
Date: 18 Sep 2000 07:56:56
Message: <39C601C9.9A919CE3@my-dejanews.com>
Part of my problem here was that I would type in noise3d(1) and assume it was
accepting it as a float of value 1.0. It was instead in its head processing
this as <1,1,1>.

There IS a problem in an inconsistent syntax for noise3d.
In function declarations you need the vector brackets <>, in isosurfaces you
must not use them!

Chris Huff wrote:

> In article <39bbc012$1@news.povray.org>, "Greg M. Johnson"
> <"gregj;-)56590\""@aol.c;-)om> wrote:
>
> > A) NOISE3D DISALLOWS APPROPRIATE NUMBER OF PARAMETERS
> >
> > First of all, the following line gives a message.
> >     #declare summy=summy+noise3d(minx,miny,minz);
> > whereas this one does not:
> >     #declare summy=summy+noise3d(minx);
> >
> > Noise3d is a function defined over 3d space; it appears to be an
> > oversight not to allow three parameters in this function.
>
> It takes a vector. :-)
> #declare summy = summy + noise3d(<minx,miny,minz>);
> I chose this because all other POV functions that take points take them
> as vectors, isosurface functions are the exception because they don't
> have vectors.
>
> > B) FUNC_ID NOT LIKED IN EXPRESSIONS.
> > It appears to be an oversight that I can insert these into an isosurface
> > but I cannot "use" these functions as is.
>
> Not an oversight, just not a feature. The isosurface functions were
> originally not intended to be used outside of isosurfaces, they weren't
> made more general until later. I am planning to attempt to implement
> this though...
> In the meantime, you can access them using eval_pattern().
>
> --
> Christopher James Huff
> Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
> TAG: chr### [at] tagpovrayorg, http://tag.povray.org/
>
> <><


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