[osg-users] Changing the loaded osg file with user interaction

maruti borker slimshadymaruti at gmail.com
Fri Sep 28 10:46:22 PDT 2007


Is changing in osg:Image  possible ??? I can apply a bump map to get that
look of an etched object , that would be fine ....  is it possible to apply
a normal map or a bump map to the loaded osg file ?? But will it be
computationally costly ??

On 8/23/07, Robert Osfield <robert.osfield at gmail.com> wrote:
>
> HI Maruti,
>
> Do you actually need to modify the geometry, could you get away with
> just modifying a texture (or more precisely the texture's osg::Image)
> ?
>
> As for the osggeometry example not showing you how to modify geometry,
> well modifying geometry is a complicated topic, your own needs are
> very very specific.  The OSG is primarily a real-time graphics API,
> its not a general purpose tool for scene construction so the API and
> examples are geared up for rendering rather than editing.
>
> Editing is possible - in fact there are modellers based on the OSG,
> but you'll need to learn about the internals of osg::Geometry and how
> to go about creating vertices, new primitives etc.  There is no easy
> way to jump in a know all this stuff, I'm afraid you'll need to be
> patient and work you way up to it.
>
> Robert.
>
> On 8/23/07, maruti borker <slimshadymaruti at gmail.com> wrote:
> > I tried out what u said , i got the node using Linesegement intersector
> ,
> > then i will got drawable class , then by using  TriangleFunctor class ,
> i am
> > able to get all the triangles with their normals , now my  i need to
> push
> > the point a bit inside so that it looks etched , so i will decrease it
> by
> > using its normal . That means divide the triangles and make 3 triangles
> ,
> > but how shud i add these triangles to the drawable class and delete the
> old
> > trianlge, and see the effect in the window . My basic doubt is how shud
> i
> > edit the mesh , i didnt find any editing in osggeometry example . :(
> >
> >  Thanx in advance
> > PS: I think just by pushing a point wont help so i need to push a a
> square
> > region :(
> >
> > On 8/11/07, Alberto Luaces < aluaces at udc.es> wrote:
> > > Could you post what you have coded so far in order to see what is
> wrong?
> > For
> > > now, just post the mesh modification code. Could it also be that you
> are
> > not
> > > calling osg::Drawable::dirtyDisplayList() so the drawable
> > never gets
> > > modified?
> > >
> > > Alberto
> > >
> > > El Sábado 11 Agosto 2007, maruti borker escribió:
> > > > I was not able to edit the mesh data.. can u give some more
> refernces ??
> > > >
> > > > On 8/8/07, Alberto Luaces <aluaces at udc.es> wrote:
> > > > > El Martes 07 Agosto 2007, maruti borker escribió:
> > > > > > HI everyone
> > > > > >                   I am  a n00b in OSG and i am using OSG 2.0 in
> > linux .
> > > > >
> > > > > I
> > > > >
> > > > > > wam developing a system which will needs an option where the
> user
> > can
> > > > > > change the loaded model by mouse clicks . The result of one
> mouse
> > click
> > > > > > shud engrave a point at that point . That is , if i drag on the
> > model
> > > > >
> > > > > and
> > > > >
> > > > > > draw a line then the line shud be engraved on the model .
> > > > > >
> > > > > > So what i did was used osgUtil::LIneSegementIntersecto
> > r::Intersection
> > > > >
> > > > > to
> > > > >
> > > > > > find the intersection and then get the points , and then move
> the
> > > > > > points
> > > > >
> > > > > in
> > > > >
> > > > > > a direction negative to the direction of the plane normal . But
> i
> > dont
> > > > >
> > > > > have
> > > > >
> > > > > > any idea to implement this any help ????
> > > > > >
> > > > > > Thanx
> > > > > > -
> > > > > > Maruti Borker
> > > > >
> > > > > Hi,
> > > > >
> > > > > as you mentioned, you can use the LineSegementIntersector, and
> then
> > get
> > > > > the
> > > > > mesh data from the nodes you picked, transform it and modify the
> > > > > drawable's
> > > > > nodes. To get and modify the mesh data of a Geode, see the
> osggeometry
> > > > > example. It can also help using the osg::TriangleFunctor class.
> > > > >
> > > > > HTH,
> > > > >
> > > > > Alberto
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> > >
> >
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> > >
> >
> >
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