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"Tek" <tek### [at] evilsuperbraincom> wrote:
> "Kenneth" <kdw### [at] earthlinknet> wrote in message
> > ...I'm essentially using the spline as an array, just
> > a holder of a certain number of random values.
>
> Nice! Are the values actually random? Have you considered using perlin noise
> instead? (i.e. f_spotted(x,0,0))
> Much of my time with POV has been spent finding interesting uses for perlin
> noise!
That's an interesting idea; hadn't considered it. (The macro just takes a
user-chosen seed value and creates its many random spline values from that.) I
don't exactly understand how I would pull a string of 'different' values out of
f_spotted(x,0,0) to create the spline with; would something like this work?
(Just a general example)...
f_spotted(200*counter,0,0) // counter is just some advancing integer
I.e., translating the pattern a fair distance each count, to get a new 'random'
value each time?
Ken
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Well I wouldn't bother using a spline. The values from spotted give a nice
smooth randomly varying result, so I'd just use f_spotted(time*speed,0,0).
Or if you want a 3D value something like
<f_spotted(T,0,0),f_spotted(T,seed1,0),f_spotted(T,seed2)> where seed1 and
seed2 randomly offset the pattern.
Alternatively you can use vturbulence(2,.5,1, T*x) which gives a vector
result and is also perlin noise based. You can increase the number of
octaves (1 in that example) to make it bumpier.
--
Tek
http://evilsuperbrain.com
"Kenneth" <kdw### [at] earthlinknet> wrote in message
news:web.4c9744cd40e56284196b08580@news.povray.org...
> "Tek" <tek### [at] evilsuperbraincom> wrote:
>> "Kenneth" <kdw### [at] earthlinknet> wrote in message
>> > ...I'm essentially using the spline as an array, just
>> > a holder of a certain number of random values.
>>
>> Nice! Are the values actually random? Have you considered using perlin
>> noise
>> instead? (i.e. f_spotted(x,0,0))
>> Much of my time with POV has been spent finding interesting uses for
>> perlin
>> noise!
>
> That's an interesting idea; hadn't considered it. (The macro just takes a
> user-chosen seed value and creates its many random spline values from
> that.) I
> don't exactly understand how I would pull a string of 'different' values
> out of
> f_spotted(x,0,0) to create the spline with; would something like this
> work?
> (Just a general example)...
>
> f_spotted(200*counter,0,0) // counter is just some advancing integer
>
> I.e., translating the pattern a fair distance each count, to get a new
> 'random'
> value each time?
>
> Ken
>
>
>
>
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John VanSickle wrote:
> The only drawback I see is that the motion of nearby clumps of grass
> should vary less than it does.
Yes. It looked more like water than air making the grass wave.
--
Darren New, San Diego CA, USA (PST)
Quoth the raven:
Need S'Mores!
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