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Crisium
PostPosted: Thu Aug 02, 2007 9:05 am    Post subject: Osg LOD Reply with quote



Joined: 02 Aug 2007
Posts: 2

Hi Quad,

I have tried to export some of the terrain in osg format and I can load it in our application with very bad framerate. I look into your osgexport and can see that only the highest level of detail is exported?

Code:

const sLODEntityTemplateElem *high_detail = lod_templ->GetLevelElem(0);
      if(high_detail->elem_interface &&
         high_detail->elem_interface->Type() == g_sdk_root->GetTypeId(iGeomEntityTemplate::TypeString())) // The LOD element is a geometry template.
      {
         ret_code = _Export_Geometry(geode, (iGeomEntityTemplate*)high_detail->elem_interface, save_images, img_type);
      }


my question is why aren't we using a osg::LOD here and export all LODs?
I know the geode is a leaf node and can't have children, but isn't this just a little rewrite and send osg::LOD to the method instead?

or is there a very good reason why you are not doing this?

Peter Wraae Marino
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ALicu
PostPosted: Thu Aug 02, 2007 11:36 am    Post subject: Reply with quote



Joined: 12 Feb 2007
Posts: 1326

Hi, we didn't include any form of LOD in the OSG export because all of our clients (using OpenSceneGraph) have their own LOD methods. They just needed the raw OSG export to see how to setup the rendering states (especially at the terrain texture layers).

Usually the slow frame is not given by the missing objects LOD, but rather by the missing terrain LOD. For terrain LOD there are various implementations from the OSG community (chunked LOD for example) you can use. I'm pretty sure that the exporter can be changed to include the objects LOD but we didn't go into much detail regarding LOD for the above mentioned reasons.

It may be that another client already implemented LODed export from Grome to OSG but I'm not aware of any public implementation. If you plan to do such implementation I'm more than happy to help you with any information.

Adrian L.
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Crisium
PostPosted: Thu Aug 02, 2007 12:21 pm    Post subject: Reply with quote



Joined: 02 Aug 2007
Posts: 2

Hi,

Do you have any links to any "chunked LOD"?

My question is how should we go by solving this problem. We are using Delta3D which is more or less just a wrapper for OSG. Osg supports paging and osg::LOD.

Peter
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ALicu
PostPosted: Thu Aug 02, 2007 12:28 pm    Post subject: Reply with quote



Joined: 12 Feb 2007
Posts: 1326

Hi Peter,

Please refer to this:

http://www.vlad1.com/~vladimir/projects/osg/

I didn't try it personally so I cannot tell you how good this implementation is.
Let me know how this is working for you, I'm very much interested in this aspect.

You can also refer to the vterrain LOD page:

http://www.vterrain.org/LOD/Implementations/

Also, I've added full rights for your user for professional edition forum, so you can browse that forum too.

Regards,
Adrian L.
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