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29 Nov 2024 06:39:02 EST (-0500)
  HeightMap Problems (Message 1 to 4 of 4)  
From: Robert Hoopes
Subject: HeightMap Problems
Date: 11 Feb 1999 04:58:50
Message: <36c2a9da.0@news.povray.org>
Hi,
In Photoshop I created a 100x100 gif image. I made a height map with this.
There is one problem, the colors I chose made the height map seem
cumbersome. What colors should I choose to make a uniform mountain range ?

Sincerely Robert Hoopes


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From: Bob Hughes
Subject: Re: HeightMap Problems
Date: 11 Feb 1999 05:44:15
Message: <36C2B466.EE084D3@aol.com>
Black to white is low to high elevation. Pretty straight forward
concept.
So use gray scale images if it's a gif or any other 256 color image.
Also black to red (green and blue is considered same as black as I
understand it, the red component is all that's considered) if bmp, tga,
png, or other greater-than-256-color image.
Basicly, a heightfield is very unlike an image_map in that the palette
index numbers don't matter for a HF, yet they do for image_maps where
the colors don't follow the index neccessarily.
And your 100 pixel square image is not a good size for a mountain range,
if you don't mind me saying so, since scaled up to just 100 pov units
this will make angular artifacts in the heightfield 1 pov unit in size.
Seen at a distance to encompass much of this terrain these will be very
obvious. A 300x300 is still pretty small for most things but will
suffice, 600x600 is a fair size. I use these sizes typically anyhow, to
each his own though.


Robert Hoopes wrote:
> 
> Hi,
> In Photoshop I created a 100x100 gif image. I made a height map with this.
> There is one problem, the colors I chose made the height map seem
> cumbersome. What colors should I choose to make a uniform mountain range ?
> 
> Sincerely Robert Hoopes

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/POVring.htm
 mailto:inv### [at] aolcom?PoV


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From: Phoenix
Subject: Re: HeightMap Problems
Date: 11 Feb 1999 08:09:28
Message: <MPG.112cf54b80c5cb48989684@news.povray.org>
'T was on Thu, 11 Feb 1999 04:43:50 -0600,
that Bob Hughes wrote:
> Basicly, a heightfield is very unlike an image_map in that the palette
> index numbers don't matter for a HF, yet they do for image_maps where
> the colors don't follow the index neccessarily.

This is not true. The docs make it very clear that the index numbers are 
used in for instance a .gif file.

Quote:
    "The color of the palette entry does not affect the height of the
     pixel. Color entry 0 could be red, blue, black or orange but the 
     height of any pixel that uses color entry 0 will always be 0. Color
     entry 255 could be indigo, hot pink, white or sky blue but the 
     height of any pixel that uses color entry 255 will always be 1."

Phoenix

-- 
eag### [at] telekabelnl                       http://users.telekabel.nl/eagle
------------------------------------------------------------------------
The POV-Ray VFAQ: http://iki.fi/warp/povVFAQ.html


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From: Bob Hughes
Subject: Re: HeightMap Problems
Date: 11 Feb 1999 19:56:24
Message: <36C37C10.E76254DA@aol.com>
Hey, thanks for clearing that up.
I must've had a lot of orderly gif palettes to not notice this. I was
going on the notion of how a palette index can be in disarray and still
be black to white for elevation! Couldn't be more wrong I guess.
It has been quite a while since I've read those old parts of the DOC.
Maybe this will teach me to re-read before I type.

Phoenix wrote:
> 
> Quote:
>     "The color of the palette entry does not affect the height of the
>      pixel. Color entry 0 could be red, blue, black or orange but the
>      height of any pixel that uses color entry 0 will always be 0. Color
>      entry 255 could be indigo, hot pink, white or sky blue but the
>      height of any pixel that uses color entry 255 will always be 1."
> 
> Phoenix
> 
> --
> eag### [at] telekabelnl                       http://users.telekabel.nl/eagle
> ------------------------------------------------------------------------
> The POV-Ray VFAQ: http://iki.fi/warp/povVFAQ.html

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/POVring.htm
 mailto:inv### [at] aolcom?PoV


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