Sounds interesting  - I'm about to fall asleep over this keyboard so I'll
give it a go tomorrozzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz!

Mick

Ron Parker <par### [at] fwicom> wrote in message
news:37851e51@news.povray.org...
> On 8 Jul 1999 17:31:34 -0400, Ron Parker wrote:
> >On Thu, 8 Jul 1999 18:45:17 +0100, Mick Hazelgrove wrote:
> >>Apart from the obligatory nag about the superpatch update :) I have a
> >>request/query
> >>
> >>Do you remember the thread about noise and basic shapes so months ago?
> >>
> >>Well is possible to add noise and to HFs? not in the sense of graphic
noise
> >>but in a way similar to that the isopatch uses.
> >>
> >>If so, if it's easy to add, can we have it?
> >
> >I'm not sure what you mean.  Are you wanting to add a higher-frequency
> >noise to a lower-frequency heightfield (i.e. more than one noise sample
> >per pixel)?
> >
> >There is a way you can fake it with the iso patch, though it's probably
> >kinda slow.  The 3.1e superpatch has a pigment function that, afaik,
> >should work with an interpolated imagemap to give you a nice isosurface
> >approximation of a heightfield.  Once you get that working, you can
> >then add any function you want to it, including noise.
>
> Here's a sample showing what I mean.  For some reason the bilinear
interpolation
> doesn't seem quite as useful as I thought it would, but here ya go anyway.
You
> should substitute your own heightfield where I have sphere.bmp.  The .001
is
> used to chop off the planar surface that would otherwise be generated by
the
> black background in my test image.
>
> file://--------- cut here ----->8=======
> camera {location <0,3,-3> look_at 0}
> light_source {<-20,20,-20> rgb <.8,.8,1>}
> light_source {<20,20,-20> rgb <1,.8,.8>}
>
> #declare xx=function{
>   pigment {
>     image_map {
>       sys "sphere.bmp"
>       interpolate 2
>     }
>   rotate 90*x
>   }
> }
>
> isosurface {
>   function{y-xx(x,y,z)+.001+.05*noise3d(20*x,20*y,20*z)}
>   bounded_by {box {0,1}}
>   eval
>   translate -.5
>   scale 3
>   texture {
>     pigment {color rgb 1}
>     finish {ambient .3}
>   }
> }
> file://--------- cut here ----->8=======

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