[osg-users] osgvolume: Swap technique in a VolumeScene fails

[Robert Osfield]

Hi Julien,

I have done a quick code review of MultipassTechnique and the
computeRenderingMode() could easily be changed to check for whether
the _volumeTile is set to avoid this specific crash, but I suspect the
root cause of the problem is elsewhere - a technique should have a
valid _volumeTile when it's in usage.  As soon as you assign a
technique to a VolumeTile the VolumeTile::setVolumeTechnique() method
sets the technique's _volumeTile pointer to itself.

I therefore suspect somehow you've created a technique but not
assigned one to a tile, but also somehow got it to be actively used.
You might be doing things correctly and there is a bug that is
lurking, or it could be something odd that you are doing.

Could you create/modify and example to illustrate this crash?

Robert.

On 9 June 2015 at 07:36, Julien Valentin <julienvalentin51 at gmail.com> wrote:
> Hi,
>
> First, excuse the lack of details of the further, i haven't been able to debug enough to understand where the bug is...
>
> So, I tried a simple scenario with the osgvolume::MultipassTechnique:
> I initialize the volume rendering with MultipassTechnique (as in the example)
> And at runtime I change it to a new osgvolume::MultipassTechnique
> It yields a weird crash in  MultipassTechnique::computeRenderingMode()
> with _volumetile==NULL ...?!
>
> So far I've debugged a lot but haven't been able to locate where that happen
> Any info would been welcome
>
> Thank you in advance
> Have a good day!
>
> Cheers,
> Julien
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=63992#63992
>
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