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  Subimage rendering bug (Message 1 to 7 of 7)  
From: Marvin
Subject: Subimage rendering bug
Date: 4 Jun 2011 17:00:01
Message: <web.4dea9c01ba0ef89e99f0841a0@news.povray.org>
Dear fellaz,

I have found what seems to be a bug in povray for Linux 3.6.1

Persistence of Vision(tm) Ray Tracer Version 3.6.1 (g++ 4.1.2 @
 x86_64-unknown-linux-gnu)

The bug is seen in what follows:

$ povray +FN +W400 +H300 +SC300 +EC399 +Omodel-000001.png radiosity3a.pov
$ model-000001.png PNG 400x300 400x300+299+0 8-bit DirectClass 21.9kb
$ povray +FN +W400 +H300 +SR0 +ER99 +SC300 +EC399 +Omodel-000001.png
radiosity3a.pov
$ identify model-000001.png                                   identify: Not
enough image data `model-000001.png'.
identify: Corrupt image `model-000001.png'.

The problem seems to be in povray itself, since partial column rendering
produces correct image with same model, which is library example with came walk
around introduced.

Workaround is to use vertical column split in division of render jobs across
cores and machines, but images will be 400x300, and not column sized.

Best regds,
Marvin


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From: clipka
Subject: Re: Subimage rendering bug
Date: 4 Jun 2011 17:20:07
Message: <4deaa187$1@news.povray.org>
Am 04.06.2011 22:56, schrieb Marvin:

> I have found what seems to be a bug in povray for Linux 3.6.1
>
> Persistence of Vision(tm) Ray Tracer Version 3.6.1 (g++ 4.1.2 @
>   x86_64-unknown-linux-gnu)
>
> The bug is seen in what follows:
>
> $ povray +FN +W400 +H300 +SC300 +EC399 +Omodel-000001.png radiosity3a.pov
> $ model-000001.png PNG 400x300 400x300+299+0 8-bit DirectClass 21.9kb
> $ povray +FN +W400 +H300 +SR0 +ER99 +SC300 +EC399 +Omodel-000001.png
> radiosity3a.pov
> $ identify model-000001.png                                   identify: Not
> enough image data `model-000001.png'.
> identify: Corrupt image `model-000001.png'.
>
> The problem seems to be in povray itself, since partial column rendering
> produces correct image with same model, which is library example with came walk
> around introduced.

This behaviour, while indeed incompatible with the PNG file format, is 
(or rather was) intentional. Old versions of POV-Ray (including 3.6x) 
used to do some pretty whacky things with some image formats.


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From: Jaime Vives Piqueres
Subject: Re: Subimage rendering bug
Date: 4 Jun 2011 17:39:42
Message: <4deaa61e$1@news.povray.org>

> Am 04.06.2011 22:56, schrieb Marvin:
>
>> I have found what seems to be a bug in povray for Linux 3.6.1
>>
>> Persistence of Vision(tm) Ray Tracer Version 3.6.1 (g++ 4.1.2 @
>> x86_64-unknown-linux-gnu)
>>
>> The bug is seen in what follows:
>>
>> $ povray +FN +W400 +H300 +SC300 +EC399 +Omodel-000001.png radiosity3a.pov
>> $ model-000001.png PNG 400x300 400x300+299+0 8-bit DirectClass 21.9kb
>> $ povray +FN +W400 +H300 +SR0 +ER99 +SC300 +EC399 +Omodel-000001.png
>> radiosity3a.pov
>> $ identify model-000001.png identify: Not
>> enough image data `model-000001.png'.
>> identify: Corrupt image `model-000001.png'.
>>
>> The problem seems to be in povray itself, since partial column rendering
>> produces correct image with same model, which is library example with
>> came walk
>> around introduced.
>
> This behaviour, while indeed incompatible with the PNG file format, is
> (or rather was) intentional. Old versions of POV-Ray (including 3.6x)
> used to do some pretty whacky things with some image formats.

  But it works fine for me, at least with my self-compiled version of 3.6.1:

 >Persistence of Vision(tm) Ray Tracer Version 3.6.1 (g++ 4.5.1 @
 > x86_64-unknown-linux-gnu)
 >...
 >Support libraries used by POV-Ray:
 >  ZLib 1.2.5, Copyright 1995-1998 Jean-loup Gailly and Mark Adler
 >  LibPNG 1.2.5, Copyright 1998-2002 Glenn Randers-Pehrson

  No corruption was found by identify, file or gimp, using the same exact
command-line with the original radiosity3.pov.

-- 
Jaime Vives Piqueres
		
La Persistencia de la Ignorancia
http://www.ignorancia.org


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From: clipka
Subject: Re: Subimage rendering bug
Date: 5 Jun 2011 05:46:47
Message: <4deb5087$1@news.povray.org>
Am 04.06.2011 23:39, schrieb Jaime Vives Piqueres:


>>> $ povray +FN +W400 +H300 +SC300 +EC399 +Omodel-000001.png
>>> radiosity3a.pov
>>> $ model-000001.png PNG 400x300 400x300+299+0 8-bit DirectClass 21.9kb
>>> $ povray +FN +W400 +H300 +SR0 +ER99 +SC300 +EC399 +Omodel-000001.png
>>> radiosity3a.pov

>> This behaviour, while indeed incompatible with the PNG file format, is
>> (or rather was) intentional. Old versions of POV-Ray (including 3.6x)
>> used to do some pretty whacky things with some image formats.
>
> But it works fine for me, at least with my self-compiled version of 3.6.1:
>...
> No corruption was found by identify, file or gimp, using the same exact
> command-line with the original radiosity3.pov.

Which command line - the first or the second?


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From: Jaime Vives Piqueres
Subject: Re: Subimage rendering bug
Date: 5 Jun 2011 06:13:39
Message: <4deb56d3@news.povray.org>

> Am 04.06.2011 23:39, schrieb Jaime Vives Piqueres:

>
>>>> $ povray +FN +W400 +H300 +SC300 +EC399 +Omodel-000001.png
>>>> radiosity3a.pov
>>>> $ model-000001.png PNG 400x300 400x300+299+0 8-bit DirectClass 21.9kb
>>>> $ povray +FN +W400 +H300 +SR0 +ER99 +SC300 +EC399 +Omodel-000001.png
>>>> radiosity3a.pov
>
>>> This behaviour, while indeed incompatible with the PNG file format, is
>>> (or rather was) intentional. Old versions of POV-Ray (including 3.6x)
>>> used to do some pretty whacky things with some image formats.
>>
>> But it works fine for me, at least with my self-compiled version of
>> 3.6.1:
>> ...
>> No corruption was found by identify, file or gimp, using the same exact
>> command-line with the original radiosity3.pov.
>
> Which command line - the first or the second?

  The second one, of course:

$ povray361 +FN +W400 +H300 +SR0 +ER99 +SC300 +EC399 +Omodel-000001.png 
radiosity3.pov
$ identify model-000001.png
model-000001.png PNG 400x300 400x300+299+0 8-bit DirectClass 4.08KB 
0.000u 0:00.000

   I even tried different variants and all of them worked... this is on 
a Linux Fedora 14.


-- 
Jaime Vives Piqueres
		
La Persistencia de la Ignorancia
http://www.ignorancia.org


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From: Marvin
Subject: Re: Subimage rendering bug
Date: 7 Jun 2011 05:00:01
Message: <web.4dede8041b52f2c673cc178a0@news.povray.org>
Jaime Vives Piqueres <jai### [at] ignoranciaorg> wrote:

> > Am 04.06.2011 23:39, schrieb Jaime Vives Piqueres:

> >
> >>>> $ povray +FN +W400 +H300 +SC300 +EC399 +Omodel-000001.png
> >>>> radiosity3a.pov
> >>>> $ model-000001.png PNG 400x300 400x300+299+0 8-bit DirectClass 21.9kb
> >>>> $ povray +FN +W400 +H300 +SR0 +ER99 +SC300 +EC399 +Omodel-000001.png
> >>>> radiosity3a.pov
> >
> >>> This behaviour, while indeed incompatible with the PNG file format, is
> >>> (or rather was) intentional. Old versions of POV-Ray (including 3.6x)
> >>> used to do some pretty whacky things with some image formats.
> >>
> >> But it works fine for me, at least with my self-compiled version of
> >> 3.6.1:
> >> ...
> >> No corruption was found by identify, file or gimp, using the same exact
> >> command-line with the original radiosity3.pov.
> >
> > Which command line - the first or the second?
>
>   The second one, of course:
>
> $ povray361 +FN +W400 +H300 +SR0 +ER99 +SC300 +EC399 +Omodel-000001.png
> radiosity3.pov
> $ identify model-000001.png
> model-000001.png PNG 400x300 400x300+299+0 8-bit DirectClass 4.08KB
> 0.000u 0:00.000
>
>    I even tried different variants and all of them worked... this is on
> a Linux Fedora 14.
>
>
> --
> Jaime Vives Piqueres
>
> La Persistencia de la Ignorancia
> http://www.ignorancia.org

I haven't been able to reproduce your step:

mtodorov@magrf:~/grc-devel/grc-0.02.07$ /usr/local/bin/povray +FN +W400 +H300
+SR0 +ER99 +SC300 +EC399 +Omodel-000001.png radiosity3a.pov
mtodorov@magrf:~/grc-devel/grc-0.02.07$ identify model000001.png
identify: Corrupt image `model-000001.png'.

Greetz, Marvin Barley Stargazer


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From: Jaime Vives Piqueres
Subject: Re: Subimage rendering bug
Date: 7 Jun 2011 07:30:14
Message: <4dee0bc6$1@news.povray.org>

> I haven't been able to reproduce your step:
>
> mtodorov@magrf:~/grc-devel/grc-0.02.07$ /usr/local/bin/povray +FN
> +W400 +H300 +SR0 +ER99 +SC300 +EC399 +Omodel-000001.png
> radiosity3a.pov mtodorov@magrf:~/grc-devel/grc-0.02.07$ identify
> model000001.png identify: Corrupt image `model-000001.png'.
>

   Marvin, are you using the official binary? If so, perhaps you can try
compiling from sources...

   Regards,

-- 
Jaime Vives Piqueres
		
La Persistencia de la Ignorancia
http://www.ignorancia.org


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