[osg-users] loading vrml segfault

John F. Richardson richards at spawar.navy.mil
Thu Sep 25 16:51:30 PDT 2008


Hello,

Probably windows only but....

Octaga has a free tool for converting from vrml1 to vrml 97 :
http://www.octaga.com/freedownloads/Vrml10to20/VRML10To20.zip 
It comes with absolutely no guarantees and no warranty.

John F. Richardson

-----Original Message-----
From: osg-users-bounces at lists.openscenegraph.org
[mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of John F.
Richardson
Sent: Thursday, September 25, 2008 10:15 AM
To: 'OpenSceneGraph Users'
Subject: Re: [osg-users] loading vrml segfault

Hello,

There is some header information that identifies the file type. So just
looking at the first few lines should identify the version. Editing the type
information can make a VRML 1.0 file believe that it is a VRML 97 file.

However, if there are serious errors in loading files then there is a node
with a field that has changed between VRML 1.0 and VRML 97.

The best place to find out such information is in the VRML 97 specification
and by looking at the various documents at www.web3d.org.

You have to search because the focus is on 3-D XML = X3D. So, some of the
VRML stuff is buried. But all the specs are there and probably archives of
the old stuff (like VRML 1.0).

One simple strategy is to preprocess and input files. This can be done
manually by inputting the file to Chisel [vrml syntax checker]

http://www2.hrp.no/vr/tools/chisel/install.htm

This will tell you what statements in the file are invalid. Then you have to
just replace them with the VRML 2 equivalent.

I thought that there was a VRML 1.0 to VRML 97 translator on the consortium
site but can't find it.

John F. Richardson

-----Original Message-----
From: osg-users-bounces at lists.openscenegraph.org
[mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of Ben Axelrod
Sent: Wednesday, September 24, 2008 11:41 AM
To: OpenSceneGraph Users
Subject: Re: [osg-users] loading vrml segfault

This page indicates that OpenInventor only supports VRML 1.0 files.
(http://www.openscenegraph.org/projects/osg/wiki/Support/UserGuides/Plugins)
And from my own experience, OpenVRML only supports VRML 2.0 files.  Can OSG
handle both of these libraries at the same time?

I am a little doubtful since the VRML file must be parsed before it can be
determined if it is VRML 1.0 or VRML 2.0.  And OpenVRML segfaults when
trying to load a VRML 1.0 file.

Does anyone have any experience supporting both VRML 1.0 and VRML 2.0 file
types?

Thanks,
-Ben

-----Original Message-----
From: osg-users-bounces at lists.openscenegraph.org
[mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of Bob Huebert
Sent: Thursday, September 18, 2008 6:20 PM
To: OpenSceneGraph Users
Subject: Re: [osg-users] loading vrml segfault

Hi Ben,

   I tried your wrl files using osg with the coin3d plugin (alternate for
some of what openvrml does) and got predictable results, given your post.

   When bombing on the Bad.wrl file, coin kindly provided the following:

% osgviewer Bad.wrl
Coin read error: Unknown field "mesh" in "VRMLShape"
         Occurred at line   5 in Bad.wrl
osgviewer: No data loaded

   Maybe this will help?

-bob

On Thu, 18 Sep 2008, Ben Axelrod wrote:

> When I try to load a VRML 1.0 file in OpenSceneGraph, it segfaults.  I am
using OpenSceneGraph 2.6, and OpenVRML 0.14.3.  I have attached the file
that causes the segfault, as well as the same file with some minor changes
to make it run properly.
>
> The segfault happens inside: osgDB::readNodeFile(filename).  It would be
great if OSG could detect the error, and return properly with an invalid
node.  But I understand if the fault is inside of OpenVRML.
>
> Thanks,
> -Ben
>
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