[osg-users] VPB and OSG Version

Jean-Sébastien Guay jean-sebastien.guay at cm-labs.com
Tue Nov 3 05:58:28 PST 2009

Hi Kim, Chris,

>   .osg files are forward compatible and in limited cases backward compatible (as long as
> the older OSG has all the necessary feature support).

And that's the catch really, some VPB versions introduced usage of some 
new features that were added to OSG at that moment, for example 
osgTerrain::Terrain techniques, and so you need to avoid using those 
features in your VPB-generated terrain database if you want it to be 
backwards-compatible. Just using the .osg format is often not enough.

>   .ive files ar coded with the file version they are built by, and will not be loaded by
> any other version of OSG.

Shouldn't that be "any *older* version"? Because .ive files created with 
OSG version X should be readable with OSG version Y if Y >= X. It's just 
the opposite which isn't true.

>   You can convert between IVE and OSG with osgconv.

Which gives you a way out, with the caveat noted above:

1. generate with VPB/OSG version X, into .osg files
2. convert to .ive with the osgconv compiled from OSG version Y

As long as you keep your versions straight, and that you avoid using 
features specific to newer versions of OSG, it should go fine. But it's 
much less trouble using a recent version of OSG everywhere, of course.

Hope that helps,

Jean-Sebastien Guay    jean-sebastien.guay at cm-labs.com

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