[osg-users] manipulating vertices from a nodeloadedbyReadNodeFile()

[Bokhorst,Rene R.]

Thanks for the link, I tried it out and finally got some results! I did encounter one more problem though. I wrote this piece of code to acquire the vertices and manipulate them.
 
void
MoveGeode(
 osg::Geode* geode,
 osg::Vec3 trans)
{
    for (unsigned int i = 0 ; i < geode->getNumDrawables() ; i += 1 ) 
 {
  osg::Drawable* drawable = geode->getDrawable(i);
  osg::Geometry* geom = dynamic_cast<osg::Geometry *>(drawable);
  for ( unsigned int ipr = 0 ; ipr < geom->getNumPrimitiveSets() ; ipr += 1)
  {
   osg::PrimitiveSet* prset = geom->getPrimitiveSet(ipr);
   osg::Vec3Array* verts = dynamic_cast<osg::Vec3Array*>(geom->getVertexArray());
   if ( verts != NULL )
   {
    unsigned int ic;
    unsigned int i2;
    unsigned int nprim=0;
    osg::notify(osg::WARN) << "Prim set type "<< prset->getMode() << std::endl;
    for ( ic = 0 ; ic < prset->getNumIndices() ; ic += 1 ) 
    { 
     // NB the vertices are held in the drawable -
     osg::notify(osg::WARN) << "vertex " << ic << " is index "<<prset->index(ic) << " at " <<
      (* verts)[prset->index(ic)].x() << "," <<
      (* verts)[prset->index(ic)].y() << "," <<
      (* verts)[prset->index(ic)].z() << std::endl;
     (* verts)[prset->index(ic)] -= trans;
     osg::notify(osg::WARN) << "vertex " << ic << " is index "<<prset->index(ic) << " at " <<
      (* verts)[prset->index(ic)].x() << "," <<
      (* verts)[prset->index(ic)].y() << "," <<
      (* verts)[prset->index(ic)].z() << std::endl;
    }
   }
  }
    }
}
 
void
MoveModel(
 osg::Node* node,
 osg::Vec3 trans)
{
 FindGeodeNodeVisitor finder;
   node->accept(finder);
   std::vector<osg::Geode*> foundGeodes = finder.GetFoundGeodes();
   for ( unsigned int i = 0 ; i < foundGeodes.size() ; i += 1 )
   {
    MoveGeode(foundGeodes[i], trans);
   }
}
 
void
SimpleOSGMapFormat::FromZeroToAbsolute(
 MapObject* mo,
 osg::ref_ptr<osg::Node> mModel)
{
 osg::BoundingBox bbound;
 bbound.expandBy(mModel->getBound());
 osg::Vec3 transPos = bbound.center();
 transPos.set(transPos.x(), transPos.y(), 0.0f);
 mo->x = transPos.x();
 mo->y = transPos.y();
 mo->z = 0.0f;//newPos.z();
 MoveModel(mModel.get(), transPos);
}
 
The first couple of vertices worked like a charm, my vertices were around (250,-250,5) as I suspected and they moved to around (0,0,5) perfectly. But then I came across some vertices that were already around (0,0,0), and they were subsequently moved to (-250, 250, 5). A quick look at the original model in milkshape confirms that this cannot be the case, so I suspect that these vertices are saved relative to something else's position. Can someone confirm this, and maybe provide me with a good overview of how these vertices are saved exactly?
 
It could have to do with how many Geodes I found in my underlying Node. I simply retrieved ALL of them, and manipulate them all equally.
 
Any ideas?
 
Regards,
 
Rene
 
PS, here's a link to one of the models I want to move to (0,0,0).
http://gentlemenguild.com/CaveEd/block_in_pompeii.middle_lod.b1369.obj
http://gentlemenguild.com/CaveEd/block_in_pompeii.middle_lod.b1369.osg
 

________________________________

Van: osg-users-bounces at lists.openscenegraph.org namens Gordon Tomlinson
Verzonden: do 26-6-2008 20:24
Aan: 'OpenSceneGraph Users'
Onderwerp: Re: [osg-users] manipulating vertices from a nodeloadedbyReadNodeFile()


Well you will have to walk the node returned by ReadNodeFile scenegraph, typically with a nodevisitor
 
until you find osg::geode, look through the sample and examples they show how to walk a scenegraph and how to create nodes and geom, the mail archives while also contain pointers if not code on how to do this
 
heres an old  example from my faq's of a nodevisitor http://www.vis-sim.com/osg/code/osgcode_bbox1.htm which also shows how to get the geodes
 

________________________________

From: osg-users-bounces at lists.openscenegraph.org [mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of Bokhorst,Rene R.
Sent: Thursday, June 26, 2008 12:25 PM
To: OpenSceneGraph Users
Subject: Re: [osg-users] manipulating vertices from a node loadedbyReadNodeFile()


thanks for replying, but the problem is that the osg::Node* returned by ReadNodeFile() is not a osg::Geode().

________________________________

From: osg-users-bounces at lists.openscenegraph.org on behalf of Serge Lages
Sent: Thu 6/26/2008 4:07 PM
To: OpenSceneGraph Users
Subject: Re: [osg-users] manipulating vertices from a node loaded byReadNodeFile()


Hi Rene,

>From you geodes, take the drawables, cast them into geometries and recover the vertex list with getVertexArray.


On Thu, Jun 26, 2008 at 3:56 PM, Bokhorst,Rene R. <r.bokhorst at fontys.nl> wrote:


	Hey there,
	
	I've been browsing the mail archive to find the answer to my question but I haven't found anything at all. I basically want to manipulate the vertices of a model loaded by the osgDB::ReadNodeFile() function. ReadNodeFile() returns a osg::Node. I was hoping this might actually be a osg::Geode, but apparently it isn't.
	
	Reason I want to do this is because I have 1600 different building models. But all of these building models are already positioned in their correct position and rotation (instead of each building being built around 0,0,0). So basically if I load my 1600 models and all position them on 0,0,0 I have a complete and perfectly aligned town. I want to move every building back to 0,0,0 so that I can re-use them. I've already used osg to find their position by finding the center of their bounding box. And now I want to substract that position from the vertices of every building and save them. Anyone know how to achieve this?
	
	Thank you in advance,
	
	Rene
	
	
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-- 
Serge Lages
http://www.tharsis-software.com <http://www.tharsis-software.com/>  

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