POV-Ray : Newsgroups : povray.programming : Possible bug in focal blur. Server Time
25 Dec 2024 22:36:08 EST (-0500)
  Possible bug in focal blur. (Message 1 to 6 of 6)  
From: Edward Coffey
Subject: Possible bug in focal blur.
Date: 12 Oct 1999 22:55:45
Message: <3803f4b1@news.povray.org>
In the scene below, the use of focal blur makes the image much brighter, as
though the blurred component is added to the original sample, rather than
some kind of (possibly weighted) average.  I'm not sure if this is supposed
to happen or not, but I've tweaked all the blur parameters to the extremes
and nothing has changed the extra brightness.  What do you think?

#version 3.1;

global_settings
{
  assumed_gamma 1.000
  ambient_light 0.000
  max_trace_level 25
}

#declare blur = 1;

camera
{
  location  < 0.000, 0.500,-1.000>
  look_at   < 0.000, 0.000, 0.000>
  #if(blur=1)
    aperture 0.100
    blur_samples 7
    focal_point < 0.000, 0.000, 0.000>
    confidence 0.900
    variance 1/128
  #end
}

light_source
{
  <-3.000, 2.500,-2.000>
  color < 1.000, 1.000, 1.000>
}

sphere
{
  < 0.000, 0.000, 0.000>, 0.200
  texture
  {
    pigment
    {
      colour < 1, 1, 1>
    }
  }
}


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From: Edward Coffey
Subject: Re: Possible bug in focal blur.
Date: 13 Oct 1999 00:36:30
Message: <38040c4e@news.povray.org>
Problem solved - there's a gamma correction applied at the end of the
focal_blur function, and I'm sure it shouldn't be there, since when you take
it out, my scenes render exactly as I think they should.
So - Am I right here?  Will this be fixed in the next version?  Will
backward compatability be maintained through use of the #version feature?


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From: Nieminen Juha
Subject: Re: Possible bug in focal blur.
Date: 13 Oct 1999 05:21:05
Message: <38044f01@news.povray.org>
I have never seen this kind of brightening when using focal blur. What's
up here?

-- 
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: Possible bug in focal blur.
Date: 13 Oct 1999 05:31:08
Message: <G1AEOLmlZvp7iT8NlsmUmOmTtMda@4ax.com>
On Wed, 13 Oct 1999 14:30:28 +1000, "Edward Coffey"
<e.c### [at] ugradunimelbeduau> wrote:

>Problem solved - there's a gamma correction applied at the end of the
>focal_blur function, and I'm sure it shouldn't be there, since when you take
>it out, my scenes render exactly as I think they should.
>So - Am I right here?  Will this be fixed in the next version?  Will
>backward compatability be maintained through use of the #version feature?

  Hi, Edward. This bug was fixed in v3.1b in January 1999. See "Changes
between POV-Ray v3.1 and v3.1g" posted in the p.a.f-a-q group. Please
consider using the latest version as there have been some significant
bugfixes since v3.1a.

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


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From: Alan Kong
Subject: Re: Possible bug in focal blur.
Date: 13 Oct 1999 05:38:02
Message: <jlIEOK7i+3duGmX6Lubwqz8wF6TL@4ax.com>
On 13 Oct 1999 05:21:05 -0400, Nieminen Juha <war### [at] punarastascstutfi>
wrote:

>  I have never seen this kind of brightening when using focal blur. What's
>up here?

  In older versions of v3.1, the gamma correction was applied twice when
using focal blur but this is no longer the case.

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


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From: Edward Coffey
Subject: Re: Possible bug in focal blur.
Date: 13 Oct 1999 18:34:29
Message: <380508f5@news.povray.org>
Alan Kong <ako### [at] pacbellNO-SPAMnet> wrote in message
news:G1AEOLmlZvp7iT8NlsmUmOmTtMda@4ax.com...
>   Hi, Edward. This bug was fixed in v3.1b in January 1999. See "Changes
> between POV-Ray v3.1 and v3.1g" posted in the p.a.f-a-q group. Please
> consider using the latest version as there have been some significant
> bugfixes since v3.1a.

From the "About POV-Ray(tm) for Windows" dialog box:
Version 3.1g.msvc.win32 [Pentium II optimised]

And the source I use under Linux is the generic UNIX 3.1g source.

I'm sorry if I've got mixed up here, but I just can't see where the problem
is - HELP :-(


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