POV-Ray : Newsgroups : povray.binaries.images : Problem with smooth heightfield Server Time
17 Aug 2024 16:17:06 EDT (-0400)
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From: JRG
Subject: Re: Problem with smooth heightfield
Date: 10 Oct 2001 17:13:43
Message: <3bc4ba07$1@news.povray.org>
"Christoph Hormann" <chr### [at] gmxde> ha scritto nel messaggio
news:3BC4B5EE.2E13A371@gmx.de...
> I know, but it's quite problematic, things have grown over the years and
> the structure of the program quite difficult to handle (in fact
> *structure* is seriously missing :-).

:-(

> I'm considering starting new from scratch, before i would like to release
> an experimental version of the current state, but there are serious
> problems with things becoming very slow after some time of use.  If i for
> example apply a filter 100 times it's getting slower and slower and i
> can't find the reason...

I lost you here... I know NOTHING about programming and similia so forgive
me if I say something silly: I always thought to h-f  utilities as image
processors which, through a series of fractal (or not) algorithms, alter (or
create from scratch) a bitmap in order to get a grayscale image usable in
POV. Once you apply a filter, you've got a new bitmap ready for other
filtering processes. No matter how many times you apply one or more filters,
every time the h-f utility treats the bitmap as if *it were the first time
it saw it*. Please tell me if I'm wrong.

--
Jonathan
> Christoph
>
> --
> Christoph Hormann <chr### [at] gmxde>
> IsoWood include, radiosity tutorial, TransSkin and other
> things on: http://www.schunter.etc.tu-bs.de/~chris/


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From: Bob H 
Subject: Re: Problem with smooth heightfield
Date: 10 Oct 2001 17:24:25
Message: <3bc4bc89@news.povray.org>
"Simon" <sim### [at] 12movede> wrote in message
news:3bc4b707@news.povray.org...
>
> Hugo <hua### [at] post3teledk> schrieb in im Newsbeitrag:
> 3bc4b311@news.povray.org...
> >
> > Thanks for the suggestion. I figured out myself that the 8 bit
resolution
> > was the problem. However, wouldn't it be possible to make an
"interpolate"
> > feature that make them appear as smooth as 16 bit?  For the user, it
would
> > be easier to stick with 8 bit bitmaps because many paintprograms don't
> > support 16 bit greys.. I don't have one, that do.
> >
> You could use your image as a image_map in a function then you could
> use interpolate.

A 'smooth' keyword exists and from what I read no one mentioned that.  Only
good on 256 color image files though from what I know.

Bob H.


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From: Bob H 
Subject: Re: Problem with smooth heightfield
Date: 10 Oct 2001 17:32:05
Message: <3bc4be55@news.povray.org>
"Christoph Hormann" <chr### [at] gmxde> wrote in message
news:3BC49D3F.5D87E8EB@gmx.de...
>
> Here are three 128x128 16 bit png's:
>
> hf_pov35_16.png      generated with POV 3.5 beta 6

Yeah gee, that's what I was talking about before, chaotic.  Odd thing is
that a Targa file will look much the same way, except for not being
grayscale, and yet can render as a HF fine.  What I saw in the PNG-made HF
was partially okay and mostly not.  Chaotic mosaics mostly.

Bob H.

> hf_pov31_16.png      generated with POV 3.1
> hf_xxx_16.png        generated with other program
>
> Christoph
>
> --
> Christoph Hormann <chr### [at] gmxde>
> IsoWood include, radiosity tutorial, TransSkin and other
> things on: http://www.schunter.etc.tu-bs.de/~chris/


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From: Christoph Hormann
Subject: Re: Problem with smooth heightfield
Date: 10 Oct 2001 17:32:38
Message: <3BC4BE76.ACE1E01E@gmx.de>
"Bob H." wrote:
> 
> A 'smooth' keyword exists and from what I read no one mentioned that.  Only
> good on 256 color image files though from what I know.
> 

'smooth' in heightfield only interpolates the normal vectors.  Geometry is
not influenced.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/


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From: Christoph Hormann
Subject: Re: Problem with smooth heightfield
Date: 10 Oct 2001 17:32:57
Message: <3BC4BE89.81EE0305@gmx.de>
JRG wrote:
> 
> I lost you here... I know NOTHING about programming and similia so forgive
> me if I say something silly: I always thought to h-f  utilities as image
> processors which, through a series of fractal (or not) algorithms, alter (or
> create from scratch) a bitmap in order to get a grayscale image usable in
> POV. Once you apply a filter, you've got a new bitmap ready for other
> filtering processes. No matter how many times you apply one or more filters,
> every time the h-f utility treats the bitmap as if *it were the first time
> it saw it*. Please tell me if I'm wrong.
> 

That's the theory, but since it is an interactive program, there are
things done after the steps (like displaying the changed bitmap) and
somewhere there must be the problem...

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/


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From: Christoph Hormann
Subject: Re: Problem with smooth heightfield
Date: 10 Oct 2001 17:40:51
Message: <3BC4C05B.EACE2539@gmx.de>
"Bob H." wrote:
> 
> Yeah gee, that's what I was talking about before, chaotic.  Odd thing is
> that a Targa file will look much the same way, except for not being
> grayscale, and yet can render as a HF fine.  What I saw in the PNG-made HF
> was partially okay and mostly not.  Chaotic mosaics mostly.
> 

Yes, it's the same pattern, but it's not chaotic, it's simply the less
significant byte, like the green channel in the tga file.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/


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From: JRG
Subject: Re: Problem with smooth heightfield
Date: 10 Oct 2001 17:41:32
Message: <3bc4c08c@news.povray.org>
So, theorically, if you apply a filter with Ategeros, save the output, then
reload it and apply a new filter the problem shouldn't sussist. I don't
think this is a *so serious* bug for a (first) beta release... :-)
BTW who would want to apply 100 filters alltogether?

--
Jonathan

"Christoph Hormann" <chr### [at] gmxde> ha scritto nel messaggio
news:3BC4BE89.81EE0305@gmx.de...
>
>
> JRG wrote:
> >
> > I lost you here... I know NOTHING about programming and similia so
forgive
> > me if I say something silly: I always thought to h-f  utilities as image
> > processors which, through a series of fractal (or not) algorithms, alter
(or
> > create from scratch) a bitmap in order to get a grayscale image usable
in
> > POV. Once you apply a filter, you've got a new bitmap ready for other
> > filtering processes. No matter how many times you apply one or more
filters,
> > every time the h-f utility treats the bitmap as if *it were the first
time
> > it saw it*. Please tell me if I'm wrong.
> >
>
> That's the theory, but since it is an interactive program, there are
> things done after the steps (like displaying the changed bitmap) and
> somewhere there must be the problem...
>
> Christoph
>
> --
> Christoph Hormann <chr### [at] gmxde>
> IsoWood include, radiosity tutorial, TransSkin and other
> things on: http://www.schunter.etc.tu-bs.de/~chris/


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From: Christoph Hormann
Subject: Re: Problem with smooth heightfield
Date: 10 Oct 2001 17:46:24
Message: <3BC4C1AC.6759C511@gmx.de>
JRG wrote:
> 
> So, theorically, if you apply a filter with Ategeros, save the output, then
> reload it and apply a new filter the problem shouldn't sussist. 

If you restart the application in between too. ;-)

> BTW who would want to apply 100 filters alltogether?
> 

When doing an animation...  

And a lot of erosion filters need to be applied a lot of times to get good
results.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/


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From: Ron Parker
Subject: Re: Problem with smooth heightfield
Date: 10 Oct 2001 17:52:07
Message: <slrn9s9goa.a1t.ron.parker@fwi.com>
On Wed, 10 Oct 2001 21:10:55 +0200, Christoph Hormann wrote:
>This is a multi-part message in MIME format.
>--------------53C58C8C78D6DC69CDEC24AB
>Content-Type: text/plain; charset=us-ascii
>Content-Transfer-Encoding: 7bit
>
>
>
>Ron Parker wrote:
>> 
>> By all means.  I'd like to see what the difference is, since I haven't
>> seen any problems with the PNGs POV outputs.
>> 
>
>Here are three 128x128 16 bit png's:
>
>hf_pov35_16.png      generated with POV 3.5 beta 6 
>hf_pov31_16.png      generated with POV 3.1
>hf_xxx_16.png        generated with other program

Only one of those works correctly with pngtopnm.  The others all have the
words in the wrong order.  I suppose this could be a flaw in pngtopnm, but
I prefer to believe that it's a flaw in everything else.

-- 
#local R=<7084844682857967,0787982,826975826580>;#macro L(P)concat(#while(P)chr(
mod(P,100)),#local P=P/100;#end"")#end background{rgb 1}text{ttf L(R.x)L(R.y)0,0
translate<-.8,0,-1>}text{ttf L(R.x)L(R.z)0,0translate<-1.6,-.75,-1>}sphere{z/9e3
4/26/2001finish{reflection 1}}//ron.parker@povray.org My opinions, nobody else's


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From: Christoph Hormann
Subject: Re: Problem with smooth heightfield
Date: 10 Oct 2001 18:08:18
Message: <3BC4C6CF.25AB0957@gmx.de>
Ron Parker wrote:
> 
> Only one of those works correctly with pngtopnm.  The others all have the
> words in the wrong order.  I suppose this could be a flaw in pngtopnm, but
> I prefer to believe that it's a flaw in everything else.
> 

Including all image viewers and paint programs that display the files with
8 bit?

Not to mention all past Povray versions and gforge etc.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/


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