POV-Ray : Newsgroups : povray.general : #read only supports 3D vectors Server Time
4 Nov 2024 21:22:04 EST (-0500)
  #read only supports 3D vectors (Message 1 to 8 of 8)  
From: None
Subject: #read only supports 3D vectors
Date: 4 Oct 2003 10:41:43
Message: <Xns940A6CCFCD48DNone@204.213.191.226>
I noticed someone mentionned this in the newsgroups a few years ago, I 
guess it's still the same?  #read only supports 3D vectors, not 2,4 or 5?  
Unless I'm doing something wrong?  (Yeah, I know, just use four seperate 
floats and reassign the 4D vector with them... just not as elegant)

Example:
//[...]
#declare CurColor = <1,1,1,0.8>;
#if (clock > 0)
  #fopen ColorFile "curcolor.dat" read
  #read (ColorFile,CurColor)  // <- Error
  #fclose ColorFile
#end

//[...]

#macro V4strC(V)
    concat("<",vstr(4,V,",",10,7),">, ")
#end

#fopen ColorFile "curcolor.dat" write
#write (ColorFile,V4strC(CurColor),"\n")
#fclose ColorFile


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From: Tim Nikias v2 0
Subject: Re: #read only supports 3D vectors
Date: 4 Oct 2003 11:50:14
Message: <3f7eec36$1@news.povray.org>
I'm not sure, but what is the error message POV spits out when trying to
load?

-- 
Tim Nikias v2.0
Homepage: http://www.digitaltwilight.de/no_lights
Email: tim.nikias (@) gmx.de


> I noticed someone mentionned this in the newsgroups a few years ago, I
> guess it's still the same?  #read only supports 3D vectors, not 2,4 or 5?
> Unless I'm doing something wrong?  (Yeah, I know, just use four seperate
> floats and reassign the 4D vector with them... just not as elegant)
>
> Example:
> //[...]
> #declare CurColor = <1,1,1,0.8>;
> #if (clock > 0)
>   #fopen ColorFile "curcolor.dat" read
>   #read (ColorFile,CurColor)  // <- Error
>   #fclose ColorFile
> #end
>
> //[...]
>
> #macro V4strC(V)
>     concat("<",vstr(4,V,",",10,7),">, ")
> #end
>
> #fopen ColorFile "curcolor.dat" write
> #write (ColorFile,V4strC(CurColor),"\n")
> #fclose ColorFile


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From: Tim Nikias v2 0
Subject: Re: #read only supports 3D vectors
Date: 4 Oct 2003 11:53:55
Message: <3f7eed13$1@news.povray.org>
Aside of that, your text looks strange to me: Just using

#write (SomeOutputFile, FourD_Vector)

suffices, no need to concat it to string first.

-- 
Tim Nikias v2.0
Homepage: http://www.digitaltwilight.de/no_lights
Email: tim.nikias (@) gmx.de



> I'm not sure, but what is the error message POV spits out when trying to
> load?
>
> -- 
> Tim Nikias v2.0
> Homepage: http://www.digitaltwilight.de/no_lights
> Email: tim.nikias (@) gmx.de
>
>
> > I noticed someone mentionned this in the newsgroups a few years ago, I
> > guess it's still the same?  #read only supports 3D vectors, not 2,4 or
5?
> > Unless I'm doing something wrong?  (Yeah, I know, just use four seperate
> > floats and reassign the 4D vector with them... just not as elegant)
> >
> > Example:
> > //[...]
> > #declare CurColor = <1,1,1,0.8>;
> > #if (clock > 0)
> >   #fopen ColorFile "curcolor.dat" read
> >   #read (ColorFile,CurColor)  // <- Error
> >   #fclose ColorFile
> > #end
> >
> > //[...]
> >
> > #macro V4strC(V)
> >     concat("<",vstr(4,V,",",10,7),">, ")
> > #end
> >
> > #fopen ColorFile "curcolor.dat" write
> > #write (ColorFile,V4strC(CurColor),"\n")
> > #fclose ColorFile
>
>
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>
>


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From: None
Subject: Re: #read only supports 3D vectors
Date: 4 Oct 2003 14:08:48
Message: <Xns940A8FEB2C3C1None@204.213.191.226>
"Tim Nikias v2.0" <tim.nikias (@) gmx.de> wrote in news:3f7eed13$1
@news.povray.org:

> Aside of that, your text looks strange to me: Just using
> 
> #write (SomeOutputFile, FourD_Vector)
> 
> suffices, no need to concat it to string first.
> 

Error is: 4D vector unexpected.

That was just an example.  Control of precision and the comma is useful 
with many data elements, might not be with a single colour, but with 
something like quaternions higher precison than the default might be 
desired. "\n" is useful for human readability.  Isn't so strange to me.


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From: JC (Exether)
Subject: Re: #read only supports 3D vectors
Date: 6 Oct 2003 02:42:33
Message: <3f810ed9@news.povray.org>
I never use the #read primitive, it's usually much easier to save in a 
POV-script format (objects declarations, array definitions and 
initialisations, etc.) and to load using the very basic #include 
primitive that has all the parsing functionalities already implemented 
(including 4D and 5D vectors).

JC

None wrote:
> I noticed someone mentionned this in the newsgroups a few years ago, I 
> guess it's still the same?  #read only supports 3D vectors, not 2,4 or 5?  
> Unless I'm doing something wrong?  (Yeah, I know, just use four seperate 
> floats and reassign the 4D vector with them... just not as elegant)
> 
> Example:
> //[...]
> #declare CurColor = <1,1,1,0.8>;
> #if (clock > 0)
>   #fopen ColorFile "curcolor.dat" read
>   #read (ColorFile,CurColor)  // <- Error
>   #fclose ColorFile
> #end
> 
> //[...]
> 
> #macro V4strC(V)
>     concat("<",vstr(4,V,",",10,7),">, ")
> #end
> 
> #fopen ColorFile "curcolor.dat" write
> #write (ColorFile,V4strC(CurColor),"\n")
> #fclose ColorFile


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From: Tim Nikias v2 0
Subject: Re: #read only supports 3D vectors
Date: 6 Oct 2003 06:18:39
Message: <3f81417f@news.povray.org>
I've never noticed that the default isn't proper. E.g. for floats, it will
just put 0.2 for 0.2, but it will use .21342 if that's the number. AFAIK,
that's the same for vectors, so what you're doing is forcing it to round to
a certain precision.

Have you looked at the output-file to see if the vector is written
correctly? And I'm not too sure, but isn't the variable you're loading a
value to (CurColor in this case) supposed to be undefined before loading?

I've never had problems using my I/O-Macs, and they support all kinds of
vectors and floats, so I'm not sure where you're problem originates...

-- 
Tim Nikias v2.0
Homepage: http://www.digitaltwilight.de/no_lights
Email: tim.nikias (@) gmx.de


> @news.povray.org:
>
> > Aside of that, your text looks strange to me: Just using
> >
> > #write (SomeOutputFile, FourD_Vector)
> >
> > suffices, no need to concat it to string first.
> >
>
> Error is: 4D vector unexpected.
>
> That was just an example.  Control of precision and the comma is useful
> with many data elements, might not be with a single colour, but with
> something like quaternions higher precison than the default might be
> desired. "\n" is useful for human readability.  Isn't so strange to me.


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From: None
Subject: Re: #read only supports 3D vectors
Date: 6 Oct 2003 12:43:15
Message: <Xns940C81678D7CDNone@204.213.191.226>
"Tim Nikias v2.0" <tim.nikias (@) gmx.de> wrote in
news:3f81417f@news.povray.org: 

> I've never noticed that the default isn't proper. E.g. for floats, it
> will just put 0.2 for 0.2, but it will use .21342 if that's the
> number. AFAIK, that's the same for vectors, so what you're doing is
> forcing it to round to a certain precision.

No, Povray uses default precision, try it.  If one of the numbers is 
really small, Povray's default will write out something like: "1.22461e-
032", which might be rounding errors I don't want to carry forward.  On 
the other hand, if one of the numbers is 1.0000005, Povray will write out 
"1", which is precision I don't want to lose.  (I'm using the Windows 
version).
 
> Have you looked at the output-file to see if the vector is written
> correctly? And I'm not too sure, but isn't the variable you're loading
> a value to (CurColor in this case) supposed to be undefined before
> loading? 

Yes, it's written correctly in the file, and... EUREKA! That's the 
problem, because I had already initialized the vector.  Hehehe, from the 
Help on #read: "A DATA_IDENTIFIER is any undeclared identifier or any 
previously declared string identifier, float identifier, or vector 
identifier.".  I guess that doesn't apply to non 3D vectors.  I've 
initialized all of my other variables and 3D vectors before reading them 
without any issues, so I didn't think about that for a 4D.

Thanks.


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From: None
Subject: Re: #read only supports 3D vectors
Date: 6 Oct 2003 12:44:10
Message: <Xns940C818EDA833None@204.213.191.226>
"JC (Exether)" <no### [at] spamfr> wrote in news:3f810ed9@news.povray.org:

> I never use the #read primitive, it's usually much easier to save in a
> POV-script format (objects declarations, array definitions and 
> initialisations, etc.) and to load using the very basic #include 
> primitive that has all the parsing functionalities already implemented
> (including 4D and 5D vectors).

Good idea!  Thanks.


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