POV-Ray : Newsgroups : povray.newusers : Image_map like decals Server Time
29 Jul 2024 10:17:33 EDT (-0400)
  Image_map like decals (Message 1 to 6 of 6)  
From: danyolgiax
Subject: Image_map like decals
Date: 2 May 2006 11:10:00
Message: <web.4457760fbc052dbba8eb78fb0@news.povray.org>
Hi!

I've got plane's wings where I want to put flags and other stuff like decals
from gif or png files...

It is possible? how?

I tried with something like this:

box
{
    <0,0,0><4,4,0.1>
    texture {
     pigment {image_map {
     png "img.png"  once
     }
}
}
}

with no results!

Dox


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From: Chris B
Subject: Re: Image_map like decals
Date: 2 May 2006 11:25:02
Message: <445779ce$1@news.povray.org>
"danyolgiax" <d.o### [at] gmailcom> wrote in message 
news:web.4457760fbc052dbba8eb78fb0@news.povray.org...
> Hi!
>
> I've got plane's wings where I want to put flags and other stuff like 
> decals
> from gif or png files...
>
> It is possible? how?
>
> I tried with something like this:
>
> box
> {
>    <0,0,0><4,4,0.1>
>    texture {
>     pigment {image_map {
>     png "img.png"  once
>     }
> }
> }
> }
>
> with no results!
>
> Dox
>

Hi Dany,

I pasted your box definition into a scene file and it worked OK for me. The 
image is only one unit by one unit by default so it initially only appeared 
in the bottom left quarter of your box, but it was there. Scaling the image 
by 4 made it fill your 4x4 unit box.

Is it possible that the problem is somewhere else in your scene - e.g. 
camera not pointing at the box , or something else blocking the cameras line 
of sight?

Regards,
Chris B.


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From: danyolgiax
Subject: Re: Image_map like decals
Date: 3 May 2006 04:55:01
Message: <web.44586fbe319c0b1aa8eb78fb0@news.povray.org>
After few tries I've resolved with this:

#declare frontlabel =
 pigment { image_map { png "train.png" // the file to read
(iff/gif/tga/png/sys)
                        map_type 0 // 0=planar, 1=spherical, 2=cylindrical,
5=torus
                        interpolate 0 // 0=none, 1=linear, 2=bilinear,
4=normalized distance
                        once
                        } // image_map
            translate <1.5,0.5,0>

            scale <3,0,0>
            translate <-4.5,-0.5,0>
           }


#declare label1 =
  pigment {
  radial
  pigment_map {
    [ 0.5 rgbt 1 ]
    [ 0.5 frontlabel ]

    } }

box {
  <0,0,0><3,1,1>
        texture { pigment {color rgb <0.5,0.5,0.5>} }
         texture { pigment { label1 } }
  }

note that train.png is 300x100 png image!

Ok it works! but I can't understand those values:

 translate <1.5,0.5,0>
 scale <3,0,0>
 translate <-4.5,-0.5,0>






"Chris B" <c_b### [at] btconnectcomnospam> wrote:
> "danyolgiax" <d.o### [at] gmailcom> wrote in message
> news:web.4457760fbc052dbba8eb78fb0@news.povray.org...
> > Hi!
> >
> > I've got plane's wings where I want to put flags and other stuff like
> > decals
> > from gif or png files...
> >
> > It is possible? how?
> >
> > I tried with something like this:
> >
> > box
> > {
> >    <0,0,0><4,4,0.1>
> >    texture {
> >     pigment {image_map {
> >     png "img.png"  once
> >     }
> > }
> > }
> > }
> >
> > with no results!
> >
> > Dox
> >
>
> Hi Dany,
>
> I pasted your box definition into a scene file and it worked OK for me. The
> image is only one unit by one unit by default so it initially only appeared
> in the bottom left quarter of your box, but it was there. Scaling the image
> by 4 made it fill your 4x4 unit box.
>
> Is it possible that the problem is somewhere else in your scene - e.g.
> camera not pointing at the box , or something else blocking the cameras line
> of sight?
>
> Regards,
> Chris B.


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From: Chris B
Subject: Re: Image_map like decals
Date: 3 May 2006 05:41:44
Message: <44587ad8$1@news.povray.org>
"danyolgiax" <d.o### [at] gmailcom> wrote in message 
news:web.44586fbe319c0b1aa8eb78fb0@news.povray.org...
>
> note that train.png is 300x100 png image!
>
> Ok it works! but I can't understand those values:
>
> translate <1.5,0.5,0>
> scale <3,0,0>
> translate <-4.5,-0.5,0>
>

Hi Dany,

The two translates seem to cancel each other out and the scale factor should 
be <3,1,1>.You should find a warning in the message stream to tell you that 
scaling by zero is not valid and that POV-Ray has automatically substituted 
'1's where you specified '0's

Despite the resolution of the image, it will always get mapped initially to 
a 1 unit square with it's bottom left corner at the origin and  its top 
right corner at x=1,y=1. By scaling the image up by a factor of 3 in the 'x' 
dimension you effectively restore the original proportions of the image.

Scaling takes place relative to the origin, so when you use translate 
'<1.5,0.5,0>' you move the bottom left corner to x=1.5,y=0.5, then scaling 
by x*3,y*1 puts the bottom left corner at x=4.5,y=0.5. Your second translate 
therefore moves the bottom left corner back to the origin.

So, all in all these three lines do the same as just specifying:
scale <3,1,1>

Hope this helps,

Regards,
Chris B.


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From: danyolgiax
Subject: Re: Image_map like decals
Date: 3 May 2006 06:50:01
Message: <web.44588abc319c0b1aa8eb78fb0@news.povray.org>
Yes! It helps! Thanks!

Theres a related problem... if I want to create a bump map for the same png
in texture?

in bump_map I cannot specify "scale"!!!


"Chris B" <c_b### [at] btconnectcomnospam> wrote:
> "danyolgiax" <d.o### [at] gmailcom> wrote in message
> news:web.44586fbe319c0b1aa8eb78fb0@news.povray.org...
> >
> > note that train.png is 300x100 png image!
> >
> > Ok it works! but I can't understand those values:
> >
> > translate <1.5,0.5,0>
> > scale <3,0,0>
> > translate <-4.5,-0.5,0>
> >
>
> Hi Dany,
>
> The two translates seem to cancel each other out and the scale factor should
> be <3,1,1>.You should find a warning in the message stream to tell you that
> scaling by zero is not valid and that POV-Ray has automatically substituted
> '1's where you specified '0's
>
> Despite the resolution of the image, it will always get mapped initially to
> a 1 unit square with it's bottom left corner at the origin and  its top
> right corner at x=1,y=1. By scaling the image up by a factor of 3 in the 'x'
> dimension you effectively restore the original proportions of the image.
>
> Scaling takes place relative to the origin, so when you use translate
> '<1.5,0.5,0>' you move the bottom left corner to x=1.5,y=0.5, then scaling
> by x*3,y*1 puts the bottom left corner at x=4.5,y=0.5. Your second translate
> therefore moves the bottom left corner back to the origin.
>
> So, all in all these three lines do the same as just specifying:
> scale <3,1,1>
>
> Hope this helps,
>
> Regards,
> Chris B.


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From: Bob H
Subject: Re: Image_map like decals
Date: 5 May 2006 06:39:57
Message: <445b2b7d$1@news.povray.org>
"danyolgiax" <d.o### [at] gmailcom> wrote in message 
news:web.44588abc319c0b1aa8eb78fb0@news.povray.org...
>
> Theres a related problem... if I want to create a bump map for the same 
> png
> in texture?
>
> in bump_map I cannot specify "scale"!!!

Jumping in to help here. Put the scale into the normal {}, outside of the 
bump_map {}.


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