[osg-submissions] Fix for reading Texture Attribute File in OpenFlight

[Andreas Ekstrand]

Hi,

As Lars mentioned, this seems to have been a typo in the OpenFlight 
specification, rather than a change in the OpenFlight format. Actually, 
all 64 bit doubles seem to begin at even 8 bytes in the ATTR file 
format, that's why we need the added padding of 4 bytes, and I think 
this has always been the case. So I'm pretty convinced that it doesn't 
break older versions. Have a look at the following conversation for this 
and a couple of other discrepancies in the OpenFlight specification:

http://www.multigen-paradigm.com/ubb/Forum8/HTML/000253.html

The other changes include another 4 bytes of padding after the comments. 
The attached file contains this change and is based on the file modified 
by Lars. The remaining issues discussed in the link above are probably 
of no great interest right now.

Funny, I thought I submitted those changes long ago, but perhaps it was 
for the old OpenFlight reader. Anyway, thanks to Lars for the spotting 
this and submitting the correction!

Regards,
Andreas Ekstrand


Robert Osfield wrote:

>Hi Lars,
>
>I've just reviewed you change and it looks like to me that it changes
>the assumed format for all version of OpenFlight files, not just a
>specific version and later as I was expecting, and therefore would
>suspect this change might break older versions of OpenFlight.
>
>As this submissions might break backwards compatibility with
>OpenFlight files I am not going to merge right now.  This issue needs
>to be fleshed out by others more knowledge of OpenFlight than myself.
>Calling Brede Johansen and Paul Martz... could you guys have a review
>of this submissions.
>
>Cheers,
>Robert.
>
>On Tue, Feb 19, 2008 at 4:44 PM, Lars Nilsson
><Lars.Nilsson at saabgroup.com> wrote:
>  
>
>>
>>
>>Hi,
>>
>>
>>
>>The change in this submission is for Texture Attribute File as described
>>from version 16.1 of OpenFlight documentation.
>>
>>In fact, I believe that it is only the documentation that has been
>>corrected, the file format was even before that the same.
>>
>>
>>
>>The attached file is based on OpenSceneGraph 2.3.4.
>>
>>
>>
>>Regards,
>>
>>Lars Nilsson
>>
>>
>>
>>
>>_______________________________________________
>> osg-submissions mailing list
>> osg-submissions at lists.openscenegraph.org
>>
>>http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org
>>
>>
>>    
>>
>_______________________________________________
>osg-submissions mailing list
>osg-submissions at lists.openscenegraph.org
>http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org
>
>  
>


-- 
______________________________________________________________
Andreas Ekstrand
Remograph
Norrbergavägen 58
SE-590 54 Sturefors
SWEDEN
Website: http://www.remograph.com/
E-mail: andreas.ekstrand at remograph.com
Phone: +46 708 490 697

-------------- next part --------------
A non-text attachment was scrubbed...
Name: ReaderWriterATTR.cpp
Type: text/x-c++src
Size: 6167 bytes
Desc: not available
Url : http://lists.openscenegraph.org/pipermail/osg-submissions-openscenegraph.org/attachments/20080226/a076ab1f/attachment.cpp