POV-Ray : Newsgroups : povray.general : Star field? Server Time: 19 Dec 2018 12:02:54 GMT
  Star field? (Message 1 to 6 of 6)  
From: Mike Horvath
Subject: Star field?
Date: 9 Aug 2018 01:49:05
Message: <5b6b9d91$1@news.povray.org>
Can anyone recommend a nice star field? The texture that comes with 
POV-Ray is not very good.

This one is okay:

http://www.hoboes.com/NetLife/POV_Simple/5/2/

Thanks.


Mike


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From: Mike Horvath
Subject: Re: Star field?
Date: 9 Aug 2018 01:50:56
Message: <5b6b9e00$1@news.povray.org>
On 8/8/2018 9:49 PM, Mike Horvath wrote:
> Can anyone recommend a nice star field? The texture that comes with 
> POV-Ray is not very good.
> 
> This one is okay:
> 
> http://www.hoboes.com/NetLife/POV_Simple/5/2/
> 
> Thanks.
> 
> 
> Mike


I also tried some public domain bitmaps, but my scene is under high 
magnification, which causes the background to appear extremely pixelated.


Mike


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From: Kenneth
Subject: Re: Star field?
Date: 10 Aug 2018 18:40:01
Message: <web.5b6ddbe518c60c30a47873e10@news.povray.org>
Mike Horvath <mik### [at] gmailcom> wrote:
> Can anyone recommend a nice star field? The texture that comes with
> POV-Ray is not very good.
>

You might want to check out Chris Colfax's old "Galaxy.inc" file; it can
apparently make 'just' starfields, with lots of settings. (I haven't used it
before-- in fact, I just downloaded it!)

Here are two sites where it's currently available...

http://objects.povworld.org/cat/Space/
and
http://www.oocities.org/ccolefax/galaxy.html

And there's always the brute-force method instead: lots of white spheres placed
way off in the distance. I would imagine that this simpler method might be less
memory-intensive than a pre-made starfield *image* (which might have to be quite
large in picel dimensions to get the proper detail, to avoid pixelation.)


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From: Kenneth
Subject: Re: Star field?
Date: 10 Aug 2018 19:20:00
Message: <web.5b6de4d418c60c30a47873e10@news.povray.org>
Mike Horvath <mik### [at] gmailcom> wrote:
>
> This one is okay:
>
> http://www.hoboes.com/NetLife/POV_Simple/5/2/
>

Interesting; I wasn't aware of this bozo-pattern technique. Thanks.


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From: Alain
Subject: Re: Star field?
Date: 10 Aug 2018 23:34:44
Message: <5b6e2114@news.povray.org>
Le 18-08-10 à 15:17, Kenneth a écrit :
> Mike Horvath <mik### [at] gmailcom> wrote:
>>
>> This one is okay:
>>
>> http://www.hoboes.com/NetLife/POV_Simple/5/2/
>>
> 
> Interesting; I wasn't aware of this bozo-pattern technique. Thanks.
> 
> 

bozo{colour_map{[0 rgb 2][0.2 rgb 0]}scale 0.006}

Looks like it rely on sub-pixel artifacts, just like the ones from the 
distribution that use granite. It's just that it use a different base 
pattern.
Just like those from skys.inc, it suffer the from same problem : Any 
movement or rotation, of the camera will cause the stars to completely 
change.
This make micro-pattern based skys unsuitable for animations.
This apply to granite, bozo(bumps, spotted), agate, crackle, cells, ... 
based patterns.
With those, you can have coloured stars.
One possible option is :
bozo{colour_map
   {[0 rgb 2]
    [0.025 rgb<2,0,0>]
    [0.0375 rgb 0]
    [0.05 rgb<0,0,2>]
    [0.075 rgb 2]
    [0.2 rgb 0]}
  scale 0.006
}


The skys from galaxy.inc don't suffer from that problem, but are more 
memory intensive, take more time to parse and are somewhat slower to render.


Alain


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From: Zeger Knaepen
Subject: Re: Star field?
Date: 14 Aug 2018 08:26:11
Message: <5b729223@news.povray.org>
try this:

sky_sphere {
   pigment {
     pigment_pattern {granite scale 3}
     pigment_map {
       [0
         crackle form <1,1,0>
         scale .0035
         color_map {
           [.35 rgb .25]
           [.55 rgb 0]
         }
       ]
       [1 rgb 0]
     }
     poly_wave .25
   }
}


it's old code, haven't tested it with any recent version of POV-Ray, but 
I suppose it'll still work.

cu!
-- 
ZK


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