Re: [osg-users] [vpb] OSGDem - generate OSG terrain with pivot?

2013-09-12 Thread Robert Osfield
Hi Fred,

You shouldn't need to do anything to handle dataset with large values, the
OSG and VPB are built to manage things for you.  When VPB builds databases
it decorates subgraphs with local transforms that place the subgraphs into
world coordinates, whilst the subgraph containing the geometry have a local
origin.  By default the OSG uses doubles for Transforms in the scene graph
and doubles in the Camera matrices, and the cull traversal accumulates
these all in doubles before finally passing a single modelview matrix to
OpenGL.  This approach ensures that you be the best possible precision when
rendering whole earth datasets.

So the answer is, stop trying so hard, everything is being done for you
already ;-)

Robert.


On 3 September 2013 14:16, Fred Dorosh  wrote:

> Hi,
>
> I am generating terrain patches which will eventually be parented in the
> scenegraph to transforms relative to a predefined runtime scene origin.
>
> When using OSGDem to generate terrain tiles from UTM-georeferenced data,
> my geometry receives very large coordinates, which I would like to
> reposition relative to a specific UTM origin.
>
> That's my goal - a hamfisted solution would be to translate everything by
> (-origin), including the PagedLOD Center, RangeLists, TerrainTiles and
> Heightfield Origin. There seems to be no built-in option to support this,
> although I imagine it's a common use case.
>
> Am I missing something obvious?
>
> Thank you!
>
> Cheers,
> Fred
>
> --
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=56086#56086
>
>
>
>
>
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[osg-users] [vpb] OSGDem - generate OSG terrain with pivot?

2013-09-12 Thread Fred Dorosh
Hi,

I am generating terrain patches which will eventually be parented in the 
scenegraph to transforms relative to a predefined runtime scene origin.

When using OSGDem to generate terrain tiles from UTM-georeferenced data, my 
geometry receives very large coordinates, which I would like to reposition 
relative to a specific UTM origin.

That's my goal - a hamfisted solution would be to translate everything by 
(-origin), including the PagedLOD Center, RangeLists, TerrainTiles and 
Heightfield Origin. There seems to be no built-in option to support this, 
although I imagine it's a common use case.

Am I missing something obvious?

Thank you!

Cheers,
Fred

--
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=56086#56086





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