[osg-users] Please test SVN version of OpenSceneGraph

Art Tevs stud_info2 at yahoo.de
Tue Sep 11 11:39:02 PDT 2007


Hi, Sicong.

The proposition you made before are not really a good
solution, since you force the compiler to use the
double version of the log function, which might be
slow.

For the integer version of the log2, I have another
proposition. I have attached a newly patched file. The
integer log2 function does compute the binary
logarithm based on the bit structure of the number.
The method seems to be faster than a double
computation of log2.

Robert, please check out if you are agree with this
version. 
Sicong, please check out if it is now working for your
system. Actually it should now.


Cheers, Art


P.S. There exists some nice methods to compute binary
logarithm really fast, but they relly on certain CPU
instructions. This function does provide a generic
solution, which might not as fast, but still fast
enough ;-)


--- sicong he <hesicong2005 at gmail.com> schrieb:

> It should be the bad VS2005 problem~~~~
> 
> 2007/9/11, sicong he <hesicong2005 at gmail.com>:
> >
> > My VS2005 report me:
> >
> > Compiler Error C2668. 'log' : ambiguous call to
> overloaded function.
> >
> > I see in VS2005, function log have only works with
> double or float:
> > double  __cdecl log(__in double _X);
> > So you should convert "int" to "double":
> > inline int log2(int v) { return
> static_cast<float>(floorf(log((double)v) *
> > INVLN_2)); }
> > But same problem happened to "floor" function. In
> VS2005 floor function
> > works with double or float, so log2 should return
> a float or double:
> > inline float log2(int v) { return
> static_cast<float>(floorf(log((double)v)
> > * INVLN_2)); }
> >
> > And this new log2 function fix the build problem.
> >
> >
> >
> >
> > 2007/9/11, Art Tevs <stud_info2 at yahoo.de>:
> >
> > > yes, it seems that math.h does not define the
> log2
> > > function on some systems.
> > >
> > > Sorry, for this.
> > >
> > > My proposition is to patch the osg's Math file
> to
> > > support for log2 method. I attached the patched
> file,
> > > which contains log2 function.
> > >
> > > Best regards, Art
> > >
> > >
> > >
> > > --- sicong he < hesicong2005 at gmail.com> schrieb:
> > >
> > > > It seems that VS2005 c++ library do not have
> log2()
> > > > function defined. So I
> > > > change log2() function to log()/log(2.0), I
> don't
> > > > know if it is slower than
> > > > log2() but it really works.
> > > >
> > > > 2007/9/11, sicong he <hesicong2005 at gmail.com>:
> > > > >
> > > > > I fixed this by change all log2(x) to:
> > > > > log((double)maximum(...))/log( 2.0)
> > > > > Then I successfully built under VS2005.
> > > > > Attachment is my patch for this problem.
> Please
> > > > test it.
> > > > >
> > > > > 2007/9/11, Shue, John <
> John.Shue at mantech-ist.com>:
> > > > > >
> > > > > >  I'm getting same compiler error on
> FreeBSD:
> > > > > > Texture1D.cpp:417: error: `log2' was not
> > > > declared in this scope
> > > > > >
> > > > > > I did:
> > > > > > # svn update
> > > > > > # ./configure
> > > > > > # make
> > > > > >
> > > > > > -john
> > > > > >
> > > > > >  ------------------------------
> > > > > > *From:*
> > > > osg-users-bounces at lists.openscenegraph.org
> [mailto:
> > > > > >
> osg-users-bounces at lists.openscenegraph.org] *On
> > > > Behalf Of *sicong he
> > > > > > *Sent:* Tuesday, September 11, 2007 10:21
> AM
> > > > > > *To:* Public OpenSceneGraph Users
> discussion
> > > > list.
> > > > > > *Subject:* Re: [osg-users] Please test SVN
> > > > version of OpenSceneGraph
> > > > > >
> > > > > >
> > > > > >  I get latest version and build under
> VS2005.
> > > > > > But in these line:
> > > > > > TextureRectangle.cpp Line 561,
> > > > TextureCubeMap.cpp Line 387,
> > > > > > Texture3D.cpp Line 459, Texture2DArray.cpp
> Line
> > > > 467, Texture2D.cpp Line
> > > > > > 411,
> > > > > > Texture1D.cpp Line 417
> > > > > > These lines VS2005 reports:
> > > > > > error C3861: "log2" can't find symbol
> > > > > > Is there some header lost?
> > > > > >
> > > > > >
> > > > > >
> > > > > > 2007/9/11, Robert Osfield
> > > > <robert.osfield at gmail.com>:
> > > > > > >
> > > > > > > Hi All,
> > > > > > >
> > > > > > > I have merged quite a few changes to the
> OSG
> > > > over the last few days,
> > > > > > > these could break the build, so I'd like
> some
> > > > feedback on how the OSG
> > > > > > > is build and running on various
> platforms
> > > > before I go ahead the weekly
> > > > > > > dev release (2.1.10).
> > > > > > >
> > > > > > > Thanks in advance,
> > > > > > > Robert.
> > > > > > >
> > > >
> _______________________________________________
> > > > > > > osg-users mailing list
> > > > > > > osg-users at lists.openscenegraph.org
> > > > > > >
> > > >
> > >
> > >
>
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> > > > > > >
> > > > > > >
> > > > > >
> > > > > > This communication, along with any
> attachments,
> > > > is covered by federal and state law governing
> > > > electronic communications and may contain
> company
> > > > proprietary and legally privileged
> information.
> > > > > > If the reader of this message is not the
> > > > intended recipient, you are hereby notified
> that any
> > > > dissemination, distribution, use or copying of
> this
> > > > message is strictly prohibited.
> > > > > > If you have received this in error, please
> reply
> > > > immediately to the sender and delete this
> message.
> > > > Thank you.
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> _______________________________________________
> > > > > > osg-users mailing list
> > > > > > osg-users at lists.openscenegraph.org
> > > > > >
> > > >
> > >
>
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> > >
> > > > > >
> > > > > >
> > > > > >
> > > > >
> > > > >
> > > > >
> _______________________________________________
> > > > osg-users mailing list
> > > > osg-users at lists.openscenegraph.org
> > > >
> > >
> > >
>
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> > > >
> > >
> > >
> > >
> > >      Heute schon einen Blick in die Zukunft von
> E-Mails wagen? Versuchen
> > > Sie´s mit dem neuen Yahoo! Mail.
> www.yahoo.de/mail
> > > _______________________________________________
> > > osg-users mailing list
> > > osg-users at lists.openscenegraph.org
> > >
>
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> > >
> 
=== message truncated ===>
_______________________________________________
> osg-users mailing list
> osg-users at lists.openscenegraph.org
>
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> 



      Die etwas anderen Infos rund um das Thema Reisen. BE A BETTER WELTENBUMMLER!  www.yahoo.de/clever
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Math
Type: application/octet-stream
Size: 8068 bytes
Desc: 2923311751-Math
URL: <http://lists.openscenegraph.org/pipermail/osg-users-openscenegraph.org/attachments/20070911/7c1654ad/attachment-0003.obj>


More information about the osg-users mailing list