POV-Ray : Newsgroups : povray.newusers : sky bleaches out ?? Server Time
5 Sep 2024 06:19:51 EDT (-0400)
  sky bleaches out ?? (Message 1 to 4 of 4)  
From: MR
Subject: sky bleaches out ??
Date: 21 Nov 2001 08:17:16
Message: <3bfba95c$1@news.povray.org>
hello,

well i'm still working on my first scene.  its a view looking
out a window.  i've placed a plane about 1000 units off
for the sky, and then i knocked out a rookie-looking sky
texture in moray.

well, the sky looks ok at 100 units off with a 100 scale but
when i get the sky plane back to around 500 units back,
it turns a drab white color, and adjusting scale doesn't seem
to help.  i would appreciate it if someone could tell me what
i need to do to fix it.  i've distilled the code and here it is.

NOTE:  this is code that looks ok, but change the plane
distance to -400 and the scale to 400 and the white really
overwhelms the white.

#declare mysky =
material
    { texture
       { pigment
          { granite
            color_map
             {
               [ 0.0     rgbft <0.435294, 1.0, 1.0, 0.0, 0.0> ]
               [ 0.153025  rgbft <0.395833, 1.0, 1.0, 0.0, 0.0> ]
               [ 1.0     rgbft <1.0, 1.0, 1.0, 0.0, 0.0> ]
             }
            turbulence 1.0
            omega 0.3
            ramp_wave
          }
         finish
           { ambient .8
           }
       }
    }
plane
  { -z, -100
   material
     { mysky
       scale 100
     }
  }
light_source
  { <150, 250, 200> color rgb 5*<1, 1, 1>
  }
camera
  {  location   <1, 1.5, -6>
     look_at    <0, 1.3, 0>
     angle      45
  }

thank you, miker


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From: Warp
Subject: Re: sky bleaches out ??
Date: 21 Nov 2001 09:06:11
Message: <3bfbb4d2@news.povray.org>
I bet that what you want is something like this (look carefully to what
I changed compared to your code):

----------8<----------8<----------8<----------8<----------8<----------
#declare mysky =
material
    { texture
       { pigment
          { granite
            color_map
             {
               [ 0.0     rgbft <1.0, 1.0, 1.0, 0.0, 1.0> ]
               [ 1.0     rgbft <1.0, 1.0, 1.0, 0.0, 0.0> ]
             }
            turbulence 1.0
            omega 0.3
            ramp_wave
          }
         finish
           { ambient 1
           }
       }
    }

sky_sphere
{ pigment
  { gradient y color_map { [0 rgb 1][.3 rgb <0,.5,1>][1 rgb z] }
  }
}

plane
  { -y, -500
    material
    { mysky
      scale 5000
    }
  }
light_source
  { <150, 250, 200>*10 color rgb <1, 1, 1>
  }
camera
  {  location   <1, 1.5, -6>
     look_at    <0, 1.3, 0>
     angle      45
  }

plane
{ y,-5
  pigment
  { granite color_map { [0 rgb <1,.8,.5>][1 rgb <.8,.4,.2>] }
    scale 10
  }
}
----------8<----------8<----------8<----------8<----------8<----------

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -


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From: MR
Subject: Re: sky bleaches out ??
Date: 21 Nov 2001 13:33:27
Message: <3bfbf377$1@news.povray.org>
thanks, warp!

its excellent!  i've looked at it quite a bit and it sent me back to
the scene language docs to check out sky_sphere.  i had seen
that but thought i could be lazy and just slap a plane up there.

i'll be honest... i'm gonna hafta back up even farther than that
and read the texture info too.  povray has no mercy for the
clueless.  hahaha.  i figured i could ignore the texture docs cuz
i've got moray and i can just slap something together using the
material editor, but then i'm trying to understand the sky_sphere
and its saying, "Since the ray direction vector is used to calculate
the pigment colors we have to use the y-gradient," and i'm saying,
"huh?"  hahaha.

but i did play with the code you gave me.  you've of course
added the sky_sphere BUT you've still used a sky plane, but
put it up in the sky like a ceiling instead of like a wall like i did.
so i'm thinking, "now wait a minute... with the sky_sphere i don't
need the sky plane anymore."  so i cut the plane and got a
plain blue sky leaning towards white at the horizon.  so i cut
the sky_sphere and all i get is black and white for the sky.

ah ha!  i'm getting a warm fuzzy here...  you've changed the
texture color map to just two colors, and it looks like one of
them is white and the other is transparent, which looks black
with no sky_sphere behind it.  so the plane is white clouds with
the blue sky_sphere showing thru!  oh yeah!  and of course
you've put a ground plane in too.

i apologize for running on and on here, but i wanted to let
you know that i'm trying to think this thru instead of just doing
a dumb cut-and-paste.

thanks again, miker


"Warp" <war### [at] tagpovrayorg> wrote in message
news:3bfbb4d2@news.povray.org...
>   I bet that what you want is something like this (look carefully to what
> I changed compared to your code):
>
> ----------8<----------8<----------8<----------8<----------8<----------
> #declare mysky =
> material
>     { texture
>        { pigment
>           { granite
>             color_map
>              {
>                [ 0.0     rgbft <1.0, 1.0, 1.0, 0.0, 1.0> ]
>                [ 1.0     rgbft <1.0, 1.0, 1.0, 0.0, 0.0> ]
>              }
>             turbulence 1.0
>             omega 0.3
>             ramp_wave
>           }
>          finish
>            { ambient 1
>            }
>        }
>     }
>
> sky_sphere
> { pigment
>   { gradient y color_map { [0 rgb 1][.3 rgb <0,.5,1>][1 rgb z] }
>   }
> }
>
> plane
>   { -y, -500
>     material
>     { mysky
>       scale 5000
>     }
>   }
> light_source
>   { <150, 250, 200>*10 color rgb <1, 1, 1>
>   }
> camera
>   {  location   <1, 1.5, -6>
>      look_at    <0, 1.3, 0>
>      angle      45
>   }
>
> plane
> { y,-5
>   pigment
>   { granite color_map { [0 rgb <1,.8,.5>][1 rgb <.8,.4,.2>] }
>     scale 10
>   }
> }
> ----------8<----------8<----------8<----------8<----------8<----------
>
> --
> #macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
> rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
> ],13),8)-3,10>#end blob{N(array[6]{11117333955,
> 7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -


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From: Warp
Subject: Re: sky bleaches out ??
Date: 21 Nov 2001 17:03:56
Message: <3bfc24cb@news.povray.org>
MR <a### [at] bnet> wrote:
: ah ha!  i'm getting a warm fuzzy here...  you've changed the
: texture color map to just two colors, and it looks like one of
: them is white and the other is transparent, which looks black
: with no sky_sphere behind it.  so the plane is white clouds with
: the blue sky_sphere showing thru!  oh yeah!  and of course
: you've put a ground plane in too.

  Yes, this is exactly the idea. The sky_sphere produces the sky-blue
(which indeed often brightens at the horizon and gets deeper blue upper in
the sky), and the plane just puts clouds horizontally up there. This is
roughly what happens in real-life as well.
  Perhaps you didn't notice, but this way the clouds actually cast shadows
on the ground (given that the "sun" is well above the clouds plane).

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -


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