POV-Ray : Newsgroups : povray.binaries.images : Image Maps (from povray.newusers) - attached files (1/1) Server Time
8 Aug 2024 01:20:19 EDT (-0400)
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From: kurtz le pirate
Subject: Image Maps (from povray.newusers) - attached files (1/1)
Date: 16 Nov 2005 13:24:14
Message: <kurtzlepirate-E03CC5.19241216112005@news.povray.org>
In article <43798cb2$1@news.povray.org>, "Slime" <fak### [at] emailaddress> 
wrote:

::> any size you like but image must have width = 2 x height.
::
::No; regardless of an image's size, it will be treated the same way by
::POV-Ray. This means it will be squeezed into the unit square from <0,0,0> to
::<1,1,0>, even if doing so changes its proportions. (If spherical mapping is
::used, the image will similarly wrap all the way around the sphere no matter
::what its width or height is.) It's up to the user to resize the image as
::necessary.
::
:: - Slime
:: [ http://www.slimeland.com/ ]

ok just look at this samples :

the difference between the two images is only the ration of the source 
image map.

when ratio is 1/2, circle is render as a cercle.
when ratio is 1/1, circle is render as an ellipse.

and the code is :
#declare ballPigment = pigment {
  image_map {
    png "image01.png" // or image02.png
    map_type 1
    interpolate 2
    }
  }

sphere {
  <0, 0, 0> 0.5
  pigment { ballPigment }
  finish { ballFinish }
  }

now, slime, can you tell me more ?
regards, klp


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Attachments:
Download 'map02.jpg' (8 KB) Download 'map01.jpg' (8 KB)

Preview of image 'map02.jpg'
map02.jpg

Preview of image 'map01.jpg'
map01.jpg


 

From: Chris B
Subject: Re: Image Maps (from povray.newusers) - attached files (1/1)
Date: 16 Nov 2005 13:56:55
Message: <437b80f7@news.povray.org>
"kurtz le pirate" <kur### [at] yahoofr> wrote in message 
news:kurtzlepirate-E03CC5.19241216112005@news.povray.org...
> In article <43798cb2$1@news.povray.org>, "Slime" <fak### [at] emailaddress>
> wrote:
>
> ::> any size you like but image must have width = 2 x height.
> ::
> ::No; regardless of an image's size, it will be treated the same way by
> ::POV-Ray. This means it will be squeezed into the unit square from 
> <0,0,0> to
> ::<1,1,0>, even if doing so changes its proportions. (If spherical mapping 
> is
> ::used, the image will similarly wrap all the way around the sphere no 
> matter
> ::what its width or height is.) It's up to the user to resize the image as
> ::necessary.
> ::
> :: - Slime
> :: [ http://www.slimeland.com/ ]
>
> ok just look at this samples :
>
> the difference between the two images is only the ratio of the source
> image map.
>
> when ratio is 1/2, circle is render as a cercle.
> when ratio is 1/1, circle is render as an ellipse.
>
> ... snip ...
>

I wouldn't want to get in the way of a good argument, but I suspect that the 
two images you started with (image01.png & image02.png) were different in 
another respect.
My guess is that the second image had a fair bit less green stripe that the 
first one had, and that the circle containing the number 14 was the same 
shape in both source images.
If you use a graphics editor to scale the first image non-uniformly by one 
half in the horizontal direction without changing the height, you should 
find that, even though the proportions will now be 1/1, the rendered image 
should still wrap correctly around the sphere.
The reason a 1/2 ratio makes a circle on the centre line of your source 
image map perfectly to a circle on the sphere of your output image is that 
the source image is wrapped around the circumference of the sphere 
horizontally and around half the circumference of the sphere vertically.

Regards,
Chris B.

--------------------------------------------------------------------------------


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From: etrask
Subject: Re: Image Maps (from povray.newusers) - attached files (1/1)
Date: 16 Nov 2005 14:50:01
Message: <web.437b8ba7aacb514e45da7f10@news.povray.org>
Perhaps the desired effect is something I am missing, but I recently made a
pool ball, number 9 to be specific, using entirely procedural methods.

#declare texSpot =
  texture {
    pigment {
      gradient z
      turbulence 0
      color_map {
        [ 0.00 color rgbt <1,1,1,1> ]
        [ 0.95 color rgbt <1,1,1,1> ]
        [ 0.95 color rgbt <1,1,1,0> ]
        [ 1.00 color rgbt <1,1,1,0> ]
      }
      scale 2
    }
  }

#declare texStripes =
  texture {
    pigment {
      gradient y
      turbulence 0
      color_map {
        [ 0.00 color rgb <1,1,1> ]
        [ 0.25 color rgb <1,1,1> ]
        [ 0.25 color rgb <0.98,0.98,0> ]
        [ 0.75 color rgb <0.98,0.98,0> ]
        [ 0.75 color rgb <1,1,1> ]
        [ 1.00 color rgb <1,1,1> ]
      }
    }
    finish {
      ambient 0
      diffuse 1
      specular 0.8
      roughness 1/128
      reflection {
        0.0625, 1/3
        fresnel on
        metallic
      }
    }
    scale 2
    translate <0,1,0>
  }
#declare text9 =
  union {
    text {
      ttf "bookos.ttf" "9" 10, 0
      translate <-0.21,-1/3,-5>
      rotate <90,0,0>
    }
    box {
      <-0.21,-0.05,-5>
      <0.3,-0.1,5>
      translate <0,-1/3,0>
      rotate <90,0,0>
    }
    translate <-0.07,0,0>
    scale 1/2
  }

#declare texText9 =
  texture {
    pigment {
      object {
        text9
        rotate <-90,0,0>
        color rgbt <1,1,1,1>
        color rgb <0,0,0> // inside
      }
      turbulence 0
      warp { planar }
    }
  }
sphere {
  <0,0,0>
  1
  texture { texPoolBall }
}


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From: Alain
Subject: Re: Image Maps (from povray.newusers) - attached files (1/1)
Date: 16 Nov 2005 19:11:41
Message: <437bcabd$1@news.povray.org>
etrask nous apporta ses lumieres en ce 2005-11-16 14:46:
> Perhaps the desired effect is something I am missing, but I recently made a
> pool ball, number 9 to be specific, using entirely procedural methods.
> 
> #declare texSpot =
>   texture {
>     pigment {
>       gradient z
>       turbulence 0
>       color_map {
>         [ 0.00 color rgbt <1,1,1,1> ]
>         [ 0.95 color rgbt <1,1,1,1> ]
>         [ 0.95 color rgbt <1,1,1,0> ]
>         [ 1.00 color rgbt <1,1,1,0> ]
>       }
>       scale 2
>     }
>   }
> 
> #declare texStripes =
>   texture {
>     pigment {
>       gradient y
>       turbulence 0
>       color_map {
>         [ 0.00 color rgb <1,1,1> ]
>         [ 0.25 color rgb <1,1,1> ]
>         [ 0.25 color rgb <0.98,0.98,0> ]
>         [ 0.75 color rgb <0.98,0.98,0> ]
>         [ 0.75 color rgb <1,1,1> ]
>         [ 1.00 color rgb <1,1,1> ]
>       }
>     }
>     finish {
>       ambient 0
>       diffuse 1
>       specular 0.8
>       roughness 1/128
>       reflection {
>         0.0625, 1/3
>         fresnel on
>         metallic
>       }
>     }
>     scale 2
>     translate <0,1,0>
>   }
> #declare text9 =
>   union {
>     text {
>       ttf "bookos.ttf" "9" 10, 0
>       translate <-0.21,-1/3,-5>
>       rotate <90,0,0>
>     }
>     box {
>       <-0.21,-0.05,-5>
>       <0.3,-0.1,5>
>       translate <0,-1/3,0>
>       rotate <90,0,0>
>     }
>     translate <-0.07,0,0>
>     scale 1/2
>   }
> 
> #declare texText9 =
>   texture {
>     pigment {
>       object {
>         text9
>         rotate <-90,0,0>
>         color rgbt <1,1,1,1>
>         color rgb <0,0,0> // inside
>       }
>       turbulence 0
>       warp { planar }
>     }
>   }
> sphere {
>   <0,0,0>
>   1
>   texture { texPoolBall }
> }
> 
> 
Why the turbulence 0?
If your object don't have an ior, fresnel does nothing. Look in the documentation for
the working.

-- 
Alain
-------------------------------------------------
File not found. Should I fake it? (Y/N)


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From: kurtz le pirate
Subject: Re: Image Maps (from povray.newusers) - attached files (1/1) - attached files (1/1)
Date: 17 Nov 2005 13:32:26
Message: <kurtzlepirate-BDBD5E.19321717112005@news.povray.org>
In article <437b80f7@news.povray.org>,
 "Chris B" <c_b### [at] btconnectcomnospam> wrote:

::I wouldn't want to get in the way of a good argument, but I suspect that the 
::two images you started with (image01.png & image02.png) were different in 
::another respect.
::My guess is that the second image had a fair bit less green stripe that the 
::first one had, and that the circle containing the number 14 was the same 
::shape in both source images.
::If you use a graphics editor to scale the first image non-uniformly by one 
::half in the horizontal direction without changing the height, you should 
::find that, even though the proportions will now be 1/1, the rendered image 
::should still wrap correctly around the sphere.
::The reason a 1/2 ratio makes a circle on the centre line of your source 
::image map perfectly to a circle on the sphere of your output image is that 
::the source image is wrapped around the circumference of the sphere 
::horizontally and around half the circumference of the sphere vertically.

sorry, here is the 2 images maps. note that in this images, circle for 
the number is a circle. image02 is not just scaled from image01.
so, if a leave a 1/1 ratio, i must draw an ellipse !

for me, image_width is wrapped along the 360 degres and the imahe_height 
is warpped from -90 to +90 degrees -> 180... and 180/360 give 1/2 ratio.

where i'm wrong ?

regards,
klp


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Attachments:
Download 'image01.jpg' (23 KB) Download 'image02.jpg' (23 KB)

Preview of image 'image01.jpg'
image01.jpg

Preview of image 'image02.jpg'
image02.jpg


 

From: etrask
Subject: Re: Image Maps (from povray.newusers) - attached files (1/1)
Date: 17 Nov 2005 16:15:01
Message: <web.437cf25aaacb514e45da7f10@news.povray.org>
When I am making a compound texture I #declare each individual part of it,
then apply it to a plane at { y, 0} so it's easier to see and tweak. I
probably am doing something wrong, but the object pattern had a lot of
turbulence to it, even without a turbulence keyword. After I set it to 0
the problem went away. I use MegaPOV 1.2, if that makes a difference.

And as for the fresnel part, it's just a habit... :P

Alain <ele### [at] netscapenet> wrote:
> Why the turbulence 0?
> If your object don't have an ior, fresnel does nothing. Look in the documentation
for the working.
>
> --
> Alain
> -------------------------------------------------
> File not found. Should I fake it? (Y/N)


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Attachments:
Download 'plan9.png' (70 KB)

Preview of image 'plan9.png'
plan9.png


 

From: Chris B
Subject: Re: Image Maps (from povray.newusers) - attached files (1/1) - attached files (1/1)
Date: 17 Nov 2005 16:16:09
Message: <437cf319$1@news.povray.org>
"kurtz le pirate" <kur### [at] yahoofr> wrote in message 
news:kurtzlepirate-BDBD5E.19321717112005@news.povray.org...
>
> where i'm wrong ?
>
> regards,
> klp
>

Only two places:
  o  at the very start of this thread (and in the previous thread) where you 
said "image must have width = 2 x height", because, technically it doesn't 
have to be 2 x height
  o  further down where you said "the difference between the two images is 
only the ratio of the source image map", which it wasn't.

It's probably a little pedantic, but if you'd just said that "width =2 x 
height is a convenient aspect ratio for this purpose" then I don't think 
anyone would have argued with you.
I think when any of us accidentally phrases something incorrectly 
(particularly on the newusers group) it's good that someone points it out in 
case it leaves others with an incorrect impression of how stuff works.
No offense intended.

Regards,
Chris B.


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From: Burki
Subject: Re: Image Maps (from povray.newusers)
Date: 18 Nov 2005 09:19:10
Message: <op.s0fwo80byrkrc2@rechner>
Kurtz le pirat wrote > Where am I wrong?

The misunderstanding came from pirate's statement "the difference between  
the two images is only the ratio of the source image map". Together with  
Slime's posting about the images that shold be "width = 2*height" it has  
caused confusion.
If both of you would refer to the width/height ratio of the NINE in your  
image it's alright.
Chris B is perfectly right in all his postings. I attached a zip  
filecontaining two scenes that should clear that fact. The zip file also  
contains the images in full size.
The first is - as you all (except etrask) did it - a cylindrical  
projection an a sphere. And it shows that it doesn't matter at all what  
the dimensions of the image are. Image "Nine_Band_sm.gif" is a 2048 x 512  
pixel image, and "Nine_Band_shrunk_sm.gif" is just made out of the latter  
by rescaling. Both will give the Niner the same appearence. I didn't post  
the rendered image cause it looks almost the same as the one that I post  
with the ...

  ... second example: It's not always necessary to use cylindrical  
projection in this cases where a relatively small image - the number nine  
- shall be glued to a billiard ball (are they're called "ball" by the  
way?). You also can use PLANAR projection in this cases. And with the  
planar projection you can fit your niners very nicely by scaling x and y  
seperately. Which you can NOT in spherical projection, there you can only  
scale the height. The width of your 9 can only be influenced with your 2D  
graphic program where you influence the width of our nine compared to the  
width of the image !
And again: it does NOT matter what height the image has got.
Really the x/y ration of an image never has an influence on its behavior  
in an image_map regardless if it is projected planar, spherical or  
cylindrical.


In my second example two niners are rendered with a gradient y to make the  
yellow stripe and two pictures of a nine, that differ only in their  
x-y-ratio (named Nine_sm.gif and Nine_stretched_sm.gif).
The red rim is made only to be filtered out in the rendering, as the nine  
is in a circle not in a square. Nice feature in the image_maps!




I posted this mainly because that ratio thing puzzled me also for quite  
some time.


Yours,
Bu.


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Attachments:
Download 'billiard_9.zip' (43 KB) Download 'nine_band_sm.gif' (4 KB) Download 'nine_band_shrunk_sm.gif' (3 KB) Download 'nine_sm.gif' (3 KB) Download 'nine_stretched_sm.gif' (3 KB) Download 'billiard_9_planar.png' (40 KB)

Preview of image 'nine_band_sm.gif'
nine_band_sm.gif

Preview of image 'nine_band_shrunk_sm.gif'
nine_band_shrunk_sm.gif

Preview of image 'nine_sm.gif'
nine_sm.gif

Preview of image 'nine_stretched_sm.gif'
nine_stretched_sm.gif

Preview of image 'billiard_9_planar.png'
billiard_9_planar.png


 

From: kurtz le pirate
Subject: Re: Image Maps (from povray.newusers)
Date: 21 Nov 2005 06:20:21
Message: <4381ad75$1@news.povray.org>

op.s0fwo80byrkrc2@rechner...
> Kurtz le pirat wrote > Where am I wrong?
>
> The misunderstanding came from pirate's statement "the difference 
> between
> the two images is only the ratio of the source image map". Together 
> with
> Slime's posting about the images that shold be "width = 2*height" it 
> has
> caused confusion.
>
> ...cutted...
>
> I posted this mainly because that ratio thing puzzled me also for 
> quite
> some time.
>
>
> Yours,
> Bu.

ok, ok. my sample is for spherical projection. now i see yours samples 
whith cylindrical and planar projection i undestand somes others 
things. but i think it's not very easy to draw an ellipse in the image 
map then use a scale (and translate) in pov source.

so, accept my apologies for my simple interpretation.
klp


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From: Burki
Subject: Re: Image Maps (from povray.newusers)
Date: 22 Nov 2005 16:00:00
Message: <web.438386a8774fbfbbd61e8c370@news.povray.org>
"kurtz_le_pirate" <kur### [at] yahoofr> wrote:
> ok, ok. my sample is for spherical projection. now i see yours samples
> whith cylindrical and planar projection i undestand somes others
> things. but i think it's not very easy to draw an ellipse in the image
> map then use a scale (and translate) in pov source.
>
> so, accept my apologies for my simple interpretation.
> klp

Hi, pirate !

Apologies are not required

       :-)

.... and you can not scale a spheric map.

Yours,
Bu.


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