"Mike Williams" <mik### [at] nospamplease> wrote in message
news:B1g### [at] econymdemoncouk...
> Wasn't it Greg M. Johnson who wrote:
> >// Consider the differences in this scene if you add fog.
> >// IMHO fog (rgb 0) should make everything darker, no?
>
> Is this the same as this known bug?
>
>         media & fog bug?
>         (Thorsten doesn't like the confirmation)
>         http://news.povray.org/3c1379e0$1@news.povray.org

I don't think so.  I shortened that scene and found it's the shadow of the
box container not mixing well with the fog as usual, still the same in beta
11 as all previous versions of POV I believe.

// buggy fog scene

#declare FogSw=1; // 1=on, 0=off
#declare MediaSw=1; //1=on, 0=off

camera {
  location <0,2,-10>
  look_at <0,0,0>
}

light_source {
  <0,9999,0>
  color rgb 1
}

#if(FogSw)
fog {
  fog_type 2
  distance 200
  fog_offset 0
  fog_alt 10
  color rgb 1
}
#end

#if(MediaSw)
box {
  <-10,10,-10>
  <10,20,10>
  material {
    texture {
  // try just 1 transparency and shadow of box begins to show
      pigment {rgbf 1.012345}
    }
    interior {
      media {
        scattering {1, 0} // no scattering(?)
        density {
          rgb 0 // no density(?)
        }
      }
    }
  }
  hollow
}
#end

plane {y,0 texture {pigment {rgb 1}}}

// END

The thing Greg was seeing seemed to be the opposite.  No darkening being
seen by a black fog spread over top of a media filled plane (the above
script has media above fog instead).
Anyway, I did see the correct* behavior in beta 10 and now still so in 11.
So I don't know what's up about that.

* And to repeat, from the horizon line and upward I see a red color which
ought not be there since no object is above -0.25*y, however the fog would
be.  Just shouldn't be solid red!  Very odd...

bob h

See changed script:

light_source {<14,2,-3> rgb 1}

box{<-500,-5,-500>,<500,-1,500> pigment {bozo scale 20}}

plane{y,-.025 pigment{rgbt 0.8}
        hollow
        interior{
                media{
                        scattering{ 1, rgb <0.25,0.5,1>}
                      }}}

fog{ rgb -.5 // darkened even further
         distance 15 fog_type 2
//fog_alt 1 fog_offset 1 // added this to fix red sky
}

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