Subject:
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Re: Mildly offtopic: POV Height Fields
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Newsgroups:
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lugnet.cad
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Date:
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Fri, 29 Jan 1999 01:40:39 GMT
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Viewed:
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1122 times
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Lee Jorgensen wrote in message <36B0F4C4.CFAAD57D@uswest.net>...
> You could try Paint Shop Pro (5.01) from http://www.jasc.com
> From my (really) quick trials, it seemed to be able to save 16-bit
> PNG format. (it had 16Million colors)
Yeah, I've got the fully paid for paintshop pro 5.0 as well. but tis doesn't
support 16bit grayscale images, only 8bit,
I guess the real problem is with pov-ray, the input format for the height
field is a bit screwy. from the pov ray help:
-------------------
A POT file is essentially a GIF file with a 16 bit palette. The maximum
number of colors in a POT file is 65536. This means a POT height field can
have up to 65536 possible height values. This makes it possible to have much
smoother height fields. Note that the maximum height of the field is still 1
even though more intermediate values are possible. At the time of this
writing the only program that created POT files was a freeware
MS-Dos/Windows program called Fractint. POT files generated with this
fractal program create fantastic landscapes.
The TGA and PPM file formats may be used as a storage device for 16 bit
numbers rather than an image file. These formats use the red and green bytes
of each pixel to store the high and low bytes of a height value. These files
are as smooth as POT files but they must be generated with special
custom-made programs. Several programs can create TGA heightfields in the
format POV uses, such as Gforge and Terrain Maker.
PNG format heightfields are usually stored in the form of a grayscale image
with black corresponding to lower and white to higher parts of the height
field. Because PNG files can store up to 16 bits in grayscale images they
will be as smooth as TGA and PPM images. Since they are grayscale images you
will be able to view them with a regular image viewer. gforge can create
16-bit heightfields in PNG format. Color PNG images will be used in the same
way as TGA and PPM images.
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The POT format is no good, I don't want a generated height field I want to
design one.
the TGA and PPM are no good as it stands because of the funny way the data
is stuffed into the pixels. I would have to write a conversion program.
What is the internal stucture of a PPM or TGA image like? I can do this, I
just need the info.
the PNG seems to be the most worthwhile, but paintshop pro only creates 8bit
grayscale, and in photoshop if I set the colour mode to grayscale, 16bits
per channel it won't give me PNG as a save option. again I could write a
program to solvew this.
This is most annoying I can't beleive an otherwise excellent product like
POV-ray is so crippled when it comes to dealing with 16-bit height fields.
Tim
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Message has 1 Reply:
 | | Re: Mildly offtopic: POV Height Fields
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| Tim McSweeney wrote in message ... (...) doesn't (...) DOH DOH DOH DOH DOH DOH DOH DOH DOH DOH ! boy do I feel stupid, reading the help file again closely I see POV also supports PGM (portable gray map) I guess I didn't notice the subtle difference (...) (26 years ago, 29-Jan-99, to lugnet.cad)
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Message is in Reply To:
| | Re: Mildly offtopic: POV Height Fields
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| You could try Paint Shop Pro (5.01) from (URL) my (really) quick trials, it seemed to be able to save 16-bit PNG format. (it had 16Million colors) -Lee. (...) -- Lee Jorgensen, Programmer/Analyst - Bankoe Systems, Inc. mailto://jorgensen@bankoe.moc (...) (26 years ago, 28-Jan-99, to lugnet.cad)
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