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From: Mark Wagner
Subject: Number_Of_Waves Bug in POV-Ray
Date: 6 Oct 1999 00:25:14
Message: <37facf2a@news.povray.org>
While looking through the POV-Ray source code, I found a bug in the code for
the "ripples" and "waves" patterns.  As part of the startup sequence, the
function Initialize_Noise() is called.  This function sets up the hash table
for Noise and DNoise, the sine table for the cycloidal modifier, and the
wave source and frequency tables for the "waves" and "ripples" patterns.
However, it is called only once, during setup for rendering.  Consequently,
the result of increasing the setting for "number_of_waves" in a scene file
to a number greater than the default of 10 (or for people using
non-command-line versions of POV, beyond the setting for the last rendered
scene) is undefined.  I'm working from the source code for v3.1e, but I
checked through the list of changes between 3.1 and 3.1g and didn't find any
mention of the bug being fixed.  To demonstrate this problem, render the
following scene twice using a non-command-line version of POV:

global_settings{number_of_waves 15}
plane{y,0 pigment{waves frequency 5}}
light_source{y*100, 1}
camera{location 1 look_at 0}

The resulting image will look significantly different the second time it is
rendered.  The setting of Number_Of_Waves is preserved between renders, but
the wave and frequency tables are regenerated with each separate trace.  The
first time the scene is rendered, the tables are generated with the default
10 wave sources, but the second time, the correct number of sources are used
for generating the tables.

Mark


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From: Nieminen Juha
Subject: Re: Number_Of_Waves Bug in POV-Ray
Date: 6 Oct 1999 05:32:55
Message: <37fb1747@news.povray.org>
Mark Wagner <mar### [at] gtenet> wrote:
: The setting of Number_Of_Waves is preserved between renders

  I have noticed that there are many things that are preserved between
renders in povwin, and many of those can be considered bugs.
  Another example is the maximum depth that was calculated (I don't remember
the exact wording of the report). Set your max_trace_level to, for example, 7
and trace a scene with glass. Povray will report the max depth as 7. No
set the max_trace level to 5 and trace. Povray will still report max depth
as being 7. If you restart povray and trace again, it will report correctly 5.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/


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From: Alan Kong
Subject: Re: Number_Of_Waves Bug in POV-Ray
Date: 11 Oct 1999 23:33:30
Message: <ZasCODQUTjAexxyHFZlltOksuBSB@4ax.com>
On 6 Oct 1999 05:32:55 -0400, Nieminen Juha <war### [at] punarastascstutfi>
wrote:

>  Another example is the maximum depth that was calculated (I don't remember
>the exact wording of the report). Set your max_trace_level to, for example, 7
>and trace a scene with glass. Povray will report the max depth as 7. No
>set the max_trace level to 5 and trace. Povray will still report max depth
>as being 7. If you restart povray and trace again, it will report correctly 5.

  Warp, pretty sure this was fixed in v3.1d. My v3.1g reports max trace
level correctly after each render.

>                       Changes as of version 3.1d
>                         --------------------------
>  
>  [..]
>  
>  o Fixed MAX_TRACE_LEVEL global not being re-initialized.
>

p.s. - hope this article posts correctly because for some reason Agent was
having a problem with which group to reply to.

-- 
Alan
http://www.povray.org - Home of the Persistence of Vision Ray Tracer


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From: Thorsten Froehlich
Subject: Re: Number_Of_Waves Bug in POV-Ray
Date: 12 Oct 1999 00:34:20
Message: <3802ba4c@news.povray.org>
In article <37facf2a@news.povray.org> , "Mark Wagner" 
<mar### [at] gtenet> wrote:

> The resulting image will look significantly different the second time it is
> rendered.  The setting of Number_Of_Waves is preserved between renders, but
> the wave and frequency tables are regenerated with each separate trace.  The
> first time the scene is rendered, the tables are generated with the default
> 10 wave sources, but the second time, the correct number of sources are used
> for generating the tables.

This bug is known and will be fixed in POV-Ray 3.5.


      Thorsten


____________________________________________________
Thorsten Froehlich
e-mail: mac### [at] povrayorg

I am a member of the POV-Ray Team.
Visit POV-Ray on the web: http://mac.povray.org


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From: Nieminen Juha
Subject: Re: Number_Of_Waves Bug in POV-Ray
Date: 12 Oct 1999 04:49:10
Message: <3802f606@news.povray.org>
Alan Kong <ako### [at] pacbellno-spamnet> wrote:
:   Warp, pretty sure this was fixed in v3.1d. My v3.1g reports max trace
: level correctly after each render.

:>  o Fixed MAX_TRACE_LEVEL global not being re-initialized.

  Sorry, I didn't realize that...
  The reason is that I haven't updated my winpov to 3.1g. The non-friendly
installation ("wipe out completely old povray and install the new on"-style)
is discouraging.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/


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From: Peter Popov
Subject: Re: Number_Of_Waves Bug in POV-Ray
Date: 12 Oct 1999 19:05:09
Message: <eKwDOGC4KyhdzgknoXAX=wkvvt6q@4ax.com>
On 12 Oct 1999 04:49:10 -0400, Nieminen Juha
<war### [at] punarastascstutfi> wrote:

>Alan Kong <ako### [at] pacbellno-spamnet> wrote:
>:   Warp, pretty sure this was fixed in v3.1d. My v3.1g reports max trace
>: level correctly after each render.
>
>:>  o Fixed MAX_TRACE_LEVEL global not being re-initialized.
>
>  Sorry, I didn't realize that...
>  The reason is that I haven't updated my winpov to 3.1g. The non-friendly
>installation ("wipe out completely old povray and install the new on"-style)
>is discouraging.

Peter Popov
ICQ: 15002700


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From: Peter Popov
Subject: Re: Number_Of_Waves Bug in POV-Ray
Date: 12 Oct 1999 20:04:39
Message: <4MsDOJhfJCJqke24oHMZAbFYzo7E@4ax.com>
On Mon, 11 Oct 1999 20:34:10 -0700, Alan Kong
<ako### [at] pacbellNO-SPAMnet> wrote:

>p.s. - hope this article posts correctly because for some reason Agent was
>having a problem with which group to reply to.

Warp, this one is for you, but I am using Agent, too, and I am having
the same problem. The Followup-to field of your post is empty and this
makes my (And Alan's) newsreader clear the "Post to which newsgroup?"
field. Please check out what your news client is up to :)


Peter Popov
ICQ: 15002700


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From: Jon A  Cruz
Subject: Re: Number_Of_Waves Bug in POV-Ray
Date: 13 Oct 1999 01:04:58
Message: <3804133B.6241D9FF@geocities.com>
Nieminen Juha wrote:

>   The reason is that I haven't updated my winpov to 3.1g. The non-friendly
> installation ("wipe out completely old povray and install the new on"-style)
> is discouraging.

At least it's not the Microsoft "reformat the hard-drive" standard solution.

--
"My new computer's got the clocks, it rocks
But it was obsolete before I opened the box" - W.A.Y.


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From: Alan Kong
Subject: Re: Number_Of_Waves Bug in POV-Ray
Date: 13 Oct 1999 05:18:05
Message: <7EwEOG271NN0gykZ=62UcgV+bPfJ@4ax.com>
On 12 Oct 1999 04:49:10 -0400, Nieminen Juha <war### [at] punarastascstutfi>
wrote:

>  The reason is that I haven't updated my winpov to 3.1g. The non-friendly
>installation ("wipe out completely old povray and install the new on"-style)
>is discouraging.

  I thought that might be the case. Now that you mention it I remember the
discussion about losing your 'good' settings during a new install.

-- 
Alan
http://www.povray.org - Home of the Persistence of Vision Ray Tracer


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From: Alan Kong
Subject: Re: Number_Of_Waves Bug in POV-Ray
Date: 13 Oct 1999 05:18:06
Message: <ok0EOOY=xql3TJjskFPo+COp59wK@4ax.com>
On Wed, 13 Oct 1999 03:03:37 +0300, Peter Popov <pet### [at] usanet> wrote:

>Warp, this one is for you, but I am using Agent, too, and I am having
>the same problem. The Followup-to field of your post is empty and this
>makes my (And Alan's) newsreader clear the "Post to which newsgroup?"
>field. Please check out what your news client is up to :)

  So that's what it is <s>. I glanced at the full header on Warp's posted
article and compared it to an earlier post but missed the empty field. I
thought I broke Agent :) Thanks for the enlightenment, Peter.

-- 
Alan
http://www.povray.org - Home of the Persistence of Vision Ray Tracer


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