Maybe others have run into this before, but I've noticed that the two
bits of code do not render the same way:

height_field { tga "land_height.tga"
               pigment { image_map { tga "land_color.tga"
                                     map_type 0 interpolate 2 }
                         rotate -90*x }
               }
 compared to

height_field { tga "land_height.tga"
               pigment { image_map { tga "land_color.tga"
                                     map_type 0 interpolate 2 once}
                         rotate -90*x }
               }

The second one is the default added by POV-Ray through the insert menu.
When I render the second bit of code the shadow looks normal, but the
height field has great patches of transparency. There is no alpha
channel on either .tga file.

I've checked this on Mac and Windows, the standard POV-Ray and MegaPov
on both platforms.

Is this a known issue or should I submit a bug report on this one?
--
Josh English
eng### [at] spiritonecom
"May your hopes, dreams, and plans not be destroyed by a few zeros."

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I think you need to translate and scale by 2 the image_map when you 
use once, because the center of the heightfield is at <0,0,0>
but not the center of the image_map (I think one of its corner is
at <0,0,0>). And you need to scale because the heightfield is
"inside" a box which have edge with 2 for length (go from -1 to 1).
But perhaps I am wrong. I am using Moray and I do like this and I
never had problems but I use material_map not image_map but I
think the process is the same :).

Fabian.


> 
> Maybe others have run into this before, but I've noticed that the two
> bits of code do not render the same way:
> 
> height_field { tga "land_height.tga"
>                pigment { image_map { tga "land_color.tga"
>                                      map_type 0 interpolate 2 }
>                          rotate -90*x }
>                }
>  compared to
> 
> height_field { tga "land_height.tga"
>                pigment { image_map { tga "land_color.tga"
>                                      map_type 0 interpolate 2 once}
>                          rotate -90*x }
>                }
> 
> The second one is the default added by POV-Ray through the insert menu.
> When I render the second bit of code the shadow looks normal, but the
> height field has great patches of transparency. There is no alpha
> channel on either .tga file.
> 
> I've checked this on Mac and Windows, the standard POV-Ray and MegaPov
> on both platforms.
> 
> Is this a known issue or should I submit a bug report on this one?
> --
> Josh English
> eng### [at] spiritonecom
> "May your hopes, dreams, and plans not be destroyed by a few zeros."

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A heightfield is always located inside a box { 0,1 } (before
transformations). The corners of an image map are at <0,0,0> and <1,1,0>
before transformations.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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The height filed is in a box from <0,0,0> to <1,1,1> and the image map is
initially placed from <0,0,0> to <1,1,0>. And I should have mentioned that
the height feild has a perfectly normal full shadow, but the surface is
transparent.

Josh

Fabian BRAU wrote:

> I think you need to translate and scale by 2 the image_map when you
> use once, because the center of the heightfield is at <0,0,0>
> but not the center of the image_map (I think one of its corner is
> at <0,0,0>). And you need to scale because the heightfield is
> "inside" a box which have edge with 2 for length (go from -1 to 1).
> But perhaps I am wrong. I am using Moray and I do like this and I
> never had problems but I use material_map not image_map but I
> think the process is the same :).
>
> Fabian.
>

> >
> > Maybe others have run into this before, but I've noticed that the two
> > bits of code do not render the same way:
> >
> > height_field { tga "land_height.tga"
> >                pigment { image_map { tga "land_color.tga"
> >                                      map_type 0 interpolate 2 }
> >                          rotate -90*x }
> >                }
> >  compared to
> >
> > height_field { tga "land_height.tga"
> >                pigment { image_map { tga "land_color.tga"
> >                                      map_type 0 interpolate 2 once}
> >                          rotate -90*x }
> >                }
> >
> > The second one is the default added by POV-Ray through the insert menu.
> > When I render the second bit of code the shadow looks normal, but the
> > height field has great patches of transparency. There is no alpha
> > channel on either .tga file.
> >
> > I've checked this on Mac and Windows, the standard POV-Ray and MegaPov
> > on both platforms.
> >
> > Is this a known issue or should I submit a bug report on this one?
> > --
> > Josh English
> > eng### [at] spiritonecom
> > "May your hopes, dreams, and plans not be destroyed by a few zeros."

--
Josh English
eng### [at] spiritonecom
"May your hopes, dreams, and plans not be destroyed by a few zeros."

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Ok, It seems to me that this is not like this with moray :).

Fabian.


> 
>   A heightfield is always located inside a box { 0,1 } (before
> transformations). The corners of an image map are at <0,0,0> and <1,1,0>
> before transformations.
> 
> --
> main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
> ):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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