[osg-users] adaptation of chunkLOD to OSG

[hann...@gmx.at]

has anyone the code of adaptation of chunkLOD to OSG by Vladimir Vukicevic?

the websites from him are all down.

it is about http://tulrich.com/geekstuff/chunklod.html

kind regards
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[Norman Vine]

hannes_b writes:
>
> has anyone the code of adaptation of chunkLOD to OSG by
> Vladimir Vukicevic?
>
> the websites from him are all down.
>
> it is about http://tulrich.com/geekstuff/chunklod.html

Maybe
http://web.archive.org/web/20070428001632/http://www.vlad1.com/~vladimir/pro
jects/osg/

HTH

Norman

[Robert Osfield]

Hi Hannes,

The OSG has native database paging rather nullifies the need for a
ChunkLOD implementation.

Vladimir's previous work on ChunkLOD/OSG implementation was done
before VirtualPlanetBuilder/osgTerrain/osgDB::DatabasePager really got
off the ground.

Robert.

[hann...@gmx.at]

Norman Vine wrote:
> hannes_b writes:
>> has anyone the code of adaptation of chunkLOD to OSG by
>> Vladimir Vukicevic?
>>
>> the websites from him are all down.
>>
>> it is about http://tulrich.com/geekstuff/chunklod.html
>
> Maybe
> http://web.archive.org/web/20070428001632/http://www.vlad1.com/~vladimir/pro
> jects/osg/
>
> HTH
>
> Norman

great help, thank you very much! :)

[hann...@gmx.at]

Robert Osfield wrote:
> Hi Hannes,
>
> The OSG has native database paging rather nullifies the need for a
> ChunkLOD implementation.
>
> Vladimir's previous work on ChunkLOD/OSG implementation was done
> before VirtualPlanetBuilder/osgTerrain/osgDB::DatabasePager really
> got off the ground.

hi robert,

someone from the project came up with this question:

> I think this demo never became part of OSG, which is also what Robert
> states in his response to your question. Anyway, I don't get what
> exactly he's talking about in terms of the relationship between
> ChunkedLOD and osgDB::DatabasePager. The chunking aspect in
> ChunkedLOD refers to the fact the rendering algorithm divides the
> terrain mesh into individual chunks that can be sent to the gfx
> adapter separately, eliminating the need to re-build the whole mesh
> every time the camera perspective changes. In my understanding,
> osgDB::DatabasePager is used to load terrain tiles in a background
> thread, but is not directly to the actual rendering operations.

[Robert Osfield]

Hi Hannes,

On Fri, Aug 29, 2008 at 8:27 PM, hann...@gmx.at <hann...@gmx.at> wrote:
> someone from the project came up with this question:

"the project" being?? Your own project?

>> I think this demo never became part of OSG, which is also what Robert
>> states in his response to your question. Anyway, I don't get what
>> exactly he's talking about in terms of the relationship between
>> ChunkedLOD and osgDB::DatabasePager. The chunking aspect in
>> ChunkedLOD refers to the fact the rendering algorithm divides the
>> terrain mesh into individual chunks that can be sent to the gfx
>> adapter separately, eliminating the need to re-build the whole mesh
>> every time the camera perspective changes. In my understanding,
>> osgDB::DatabasePager is used to load terrain tiles in a background
>> thread, but is not directly to the actual rendering operations.

DatabasePager only does loading of subgraps in a background thread,
incremental compiling of OpenGL objects, merge of new subgraphs and
deleting of expired subgraphs. This is not equivalent to ChunkedLOD,
rather just one component of such as system, although I'd guess
DatabasePager is far more capable than most paging systems that you'll
find on ChunkedLOD implementations.

The division of the database up is pre-processing step that is done by
VirtualPlanetBuilder, which builds a hierarchical tiled database. VTP
is extremely scalable and can terrabyte geospatial whole earth
databases. All the databases generated by VTB are viewable in OSG
applications, with the DatabasePager managing the paging automatically
for you, and either standard osg::Geometry/osg::StateSet/osg::Node
subgraphs or osgTerrain based subgraphs handling the scene
representation and rendering. VTB is the only source tool of its
kind as far as I'm aware.

Put osgDB::DatabasePager and VTP generated databases together and you
have something that is far more scalable and capable than a ChunkedLOD
implementation.

Robert.

[hann...@gmx.at]

Robert Osfield wrote:
> Hi Hannes,
>
> On Fri, Aug 29, 2008 at 8:27 PM, hann...@gmx.at <hann...@gmx.at> wrote:
>> someone from the project came up with this question:
>
> "the project" being?? Your own project?

http://sourceforge.net/projects/csp
http://csp.sourceforge.net/
The Combat Simulator Project

originally someone did a test with photo realistic terrain.
video (40s):
High resolution (26 Mo) http://documents.cigognes.net/csp/csp-terrain-photo.avi
Low resolution (YouTube) http://fr.youtube.com/watch?v=1NlZoylXrlo

we are a little bit confused.
http://csp.sourceforge.net/forum/viewtopic.php?p=4616#4616

is http://www.openscenegraph.org/projects/osg/wiki/Support/UserGuides/osgdem what you mean or are we on the wrong way?

with VirtualPlanetBuilder you mean http://www.openscenegraph.org/projects/VirtualPlanetBuilder
with VTP you mean http://www.vterrain.org/
i did not find anything about VTB, is it a mistyped VTP?

thanks for your help in our confusion.

best regards

[Alberto Luaces]

Just a little remark: isn't the cockpit supposed to read "FUEL FLOW" instead
of "FLUEL FLOW"? :)

> originally someone did a test with photo realistic terrain.
> video (40s):
> High resolution (26 Mo)
> http://documents.cigognes.net/csp/csp-terrain-photo.avi Low resolution
> (YouTube) http://fr.youtube.com/watch?v=1NlZoylXrlo
>

_______________________________________________

[hann...@gmx.at]

LOL, yes you are right, i never saw that.

thank you for finding the failure. :)

[Robert Osfield]

Hi Hannes,

On Thu, Sep 4, 2008 at 8:36 PM, hann...@gmx.at <hann...@gmx.at> wrote:
> with VirtualPlanetBuilder you mean
> http://www.openscenegraph.org/projects/VirtualPlanetBuilder
> with VTP you mean http://www.vterrain.org/
> i did not find anything about VTB, is it a mistyped VTP?

It's a typo - VTB should be VPB i.e. VirtualPlanetBuilder.

Robert.