POV-Ray : Newsgroups : povray.unofficial.patches : Re: bug: crackle metric 1 (9kbbu) Server Time
1 Sep 2024 20:20:02 EDT (-0400)
  Re: bug: crackle metric 1 (9kbbu) (Message 1 to 6 of 6)  
From: Ron Parker
Subject: Re: bug: crackle metric 1 (9kbbu)
Date: 18 Sep 2000 11:22:53
Message: <slrn8scdiv.3s4.ron.parker@fwi.com>

>Anton Sherwood wrote:
>> 
>> crackle solid metric 0.9, 1.0, 1.1
>> 
>	Shouldn't metric be always an integer? metric 1 looks like what I would
>expect anyway...

There is no reason why metric must be an integer, though using values other
than 1 or 2 can slow down the rendering.  Metric 1 looks like it's broken,
and in fact it is:

    VSub(dv, TPat->Vals.Crackle.cv[i], tv);

        if ( UseSquare ) {
            sum  = VSumSqr(dv);
                if ( Offset ) sum += Offset*Offset;
        }
    else if ( UseUnity ) {
            sum = dv[X] + dv[Y] + dv[Z];
            if ( Offset ) sum += Offset;
    }
    else {
            sum = pow( fabs( dv[X] ), Metric ) +
                      pow( fabs( dv[Y] ), Metric ) +
                          pow( fabs( dv[Z] ), Metric );
            if ( Offset ) sum += pow( Offset, Metric );
    }

Note that in the metric=1 case (UseUnity) it doesn't take the absolute
values of the components of dv, whereas in the default case it does.  The
default case is the correct one.  This same fix must be made in the case 
of the three minimum distance calculations before the loop.

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.


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From: Jérôme Berger
Subject: Re: bug: crackle metric 1 (9kbbu)
Date: 18 Sep 2000 11:49:00
Message: <39C63AC8.B537847B@enst.fr>
Ron Parker wrote:
> 
> Note that in the metric=1 case (UseUnity) it doesn't take the absolute
> values of the components of dv, whereas in the default case it does.  The
> default case is the correct one.  This same fix must be made in the case
> of the three minimum distance calculations before the loop.
> 
	Point. I only looked at the image and didn't see anything amiss in the
metrics 1 case (I'm completely unable to say what the others should look
like anyway...)


-- 

* Doctor Jekyll had something * mailto:ber### [at] inamecom
* to Hyde...                  * http://www.enst.fr/~jberger
*******************************


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From: Anton Sherwood
Subject: Re: bug: crackle metric 1 (9kbbu)
Date: 30 Sep 2000 14:26:44
Message: <39D63201.19836DFA@pobox.com>
Ron Parker wrote:
	[code]
> Note that in the metric=1 case (UseUnity) it doesn't take the absolute
> values of the components of dv, whereas in the default case it does.  The
> default case is the correct one.  This same fix must be made in the case
> of the three minimum distance calculations before the loop.

okay, what file is this in?

-- 
Anton Sherwood  --  br0### [at] p0b0xcom  --  http://ogre.nu/


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From: Anton Sherwood
Subject: Re: bug: crackle metric 1 (9kbbu)
Date: 30 Sep 2000 14:29:33
Message: <39D632AB.B76DB5F1@pobox.com>

> I only looked at the image and didn't see anything amiss in the
> metrics 1 case (I'm completely unable to say what the others
> should look like anyway...)

The point of the image was that cases 0.9 and 1.1 strongly resemble each
other while 1.0 looks nothing like them.

-- 
Anton Sherwood  --  br0### [at] p0b0xcom  --  http://ogre.nu/


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From: Ron Parker
Subject: Re: bug: crackle metric 1 (9kbbu)
Date: 1 Oct 2000 20:42:45
Message: <slrn8tfnek.fnl.ron.parker@fwi.com>
On Sat, 30 Sep 2000 11:33:37 -0700, Anton Sherwood wrote:
>Ron Parker wrote:
>	[code]
>> Note that in the metric=1 case (UseUnity) it doesn't take the absolute
>> values of the components of dv, whereas in the default case it does.  The
>> default case is the correct one.  This same fix must be made in the case
>> of the three minimum distance calculations before the loop.
>
>okay, what file is this in?

pattern.c


-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.
Proudly not helping RIAA and SDMI steal my rights -- 
  http://www.eff.org/Misc/EFF/Newsletters/EFFector/HTML/effect13.08.html


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From: Jérôme Berger
Subject: Re: bug: crackle metric 1 (9kbbu)
Date: 2 Oct 2000 10:46:07
Message: <39D89FAE.C2C1C7B@enst.fr>
Anton Sherwood wrote:
> 

> > I only looked at the image and didn't see anything amiss in the
> > metrics 1 case (I'm completely unable to say what the others
> > should look like anyway...)
> 
> The point of the image was that cases 0.9 and 1.1 strongly resemble each
> other while 1.0 looks nothing like them.
> 
	Yes, but the case 1.0 looks exactly like I'd expect so if there is a
problem, it's likely in the others (but I don't think so, changing
metrics is not a continuous operation...)


-- 

* Doctor Jekyll had something * mailto:ber### [at] inamecom
* to Hyde...                  * http://www.enst.fr/~jberger
*******************************


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