Christoph Hormann wrote:

> Tor Olav Kristensen wrote:
> 
>>
>> You can give the periodic interval as an argument to the
>> macro. This makes it easy to study the periodicity when
>> the interval is set small.
> 
> 
> For most purposes the noise generator should have a periodicity as large 
> as possible.
> 
>> Do you know where the 'far areas' are and how the functions
>> typically degenerates ?
> 
> 
> try rendering:
> 
> camera {
>   orthographic
>   location <0,0,1>
>   look_at  <0,0,0>
>   right 1*x
>   up 1*y
> }
> 
> box {
>   <-0.5, -0.5, 0>, <0.5, 0.5, 0>
>   texture {
>     pigment {
>       bozo
>       color_map {
>         [0.0 color rgb 0.0 ]
>         [1.0 color rgb 1.0 ]
>       }
>       scale 0.01
>       translate 3e7*x
>     }
>     finish {
>       ambient 1.0
>       diffuse 0.0
>     }
>   }
> }

I see. But this works ok:

     pigment {
       function { f_noise3d(x + 3e7, y, z) }
       color_map {
         [0.0 color rgb 0.0 ]
         [1.0 color rgb 1.0 ]
       }
       scale 0.01
     }


>>  > 2) performance.  This is quite impossible to conclude from an
>>
>>> SDL version.
>>
>>
>>
>> Why is that ?
>>
>> The macro can produce noise functions that behave simlar
>> to f_noise3d()
> 
> 
> But much slower.  The noise generator is quite critical for the render 
> speed in a lot of scenes.  That's why the Windows version of POV-Ray 
> contains a special hand optimized version of the noise function.

Nice to know.


-- 
Tor Olav
http://subcube.net
http://subcube.com

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