Le Fri, 11 Dec 2009 17:20:14 +0100, Chris 'Xenon' Hanson <xe...@alphapixel.com>
a écrit:
On 12/11/2009 7:54 AM, Sukender wrote:
Hi all,
I've got model tiles (urban zone, files such as .osg/ive, .3ds ...) which need
to be visualized using pagedLODs.
Can VPB do with models what it does with terrain? That is to say, can VPB help
me in a way or another to:
- Create less detailed version of the tiles? (Am I a bit optimistic?)
- Arrange tiles under LODs/pagedLODs into a master file?
- Deform tiles according to coordinates system? (I guess so, using OGR?)
If answers are "no", do you have an idea on how to acheive this goal?
The answers, in my experience are no, no and no. ;)
Can you clarify what your tiles are exactly? Are they a ground surface and
building on
top of them?
Exactly! I can separate ground from other models of course. I can have DEM
instead of terrain mesh too.
If so, I don't expect VPB would ever be able to do #1 for you. Creating lower
LODs of
arbitrary geometry is sort of beyond its scope.
Do you know anything that could help simplifying meshs/generatie lower LODs?
#2 would be nice, but isn't done at this time. My experience is that the usual
work-around is to install callbacks on the PagedLOD load so that when a new
VPB-created
terrain tile is loaded, your callback is invoked and can locate, load and
attach any
cultural decorations like buildings and such.
I'm not sure I understand. Can you precise how you do this? What do you mean by "a
new VPB-created terrain tile is loaded"?
#3: OGR is probably way too slow to do this. There might be a way to
translate your
model in advance into the same coordinate system VPB builds your data into
(often
geographic lat/lon) and then employ a technique similar to osgTerrain::Locator
to then
transform those coordinates into 3D space so that they come deformed the same
way the
terrain tiles do. I believe it's the Locator that performs the Earth-curvature
process.
Well I'd like to do offline processing, so OGR might be enough... or is it so
slow that even offline processing would be too long?
Thank you.
--
Sukender
PVLE - Lightweight cross-platform game engine - http://pvle.sourceforge.net/
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