[vtkusers] Per triangle texturing. Please help!!

[Wes Turner]

You shouldn't change the point coordinates at the output of a filter ... the
output is generated automatically based on the input to the filter and your
changes will be lost the next time that the filter executes.  If you need to
change the point coordinates, you need to first disconnect the output from
the pipeline.  An easy way to do this is to declare a new PolyData and do a
deep copy from the output of the filter into the new PolyData.  Once you do
this, you should find that any changes you make to the new persist.

- Wes

On 9/4/07, Samuel Marcos <godofredoiii at gmail.com> wrote:
>
> Hi Tim, many thanks
> I've read something similar in another thread. I've been trying to add
> texture coords in a simple example using vtkjpegreader, but I don't get any
> good results. What I do is to add Tcoords to a polydata, then map the
> polydata whit a Polydatamapper and then add the mapper and a texture to the
> actor. Is that correct?
> Also I would like to keep the question of my first post hot: Is it
> possible to change Polydata point values in a vtkTextureMapToPlane but
> keeping the rest of the information?
>
> On 9/3/07, Tim Hutton <tim.hutton at gmail.com> wrote:
> >
> > Hi Godofredo,
> >
> > VTK doesn't support per-face texturing natively. You can get the same
> > effect by splitting the vertices - duplicating them so that at a
> > junction between e.g. 6 triangles, there are 6 vertices, all with the
> > same spatial coordinates but different texture coordinates.
> >
> > If you look in vtkOBJReader that's the approach it uses where
> > necessary, to read-in the OBJ format (which does support per-face
> > textures).
> >
> > To manipulate the texture coordinates, just use
> > my_polydata->GetPointData()->GetTCoords().
> >
> > Tim
> >
> > On 03/09/07, Godofredo <godofredoiii at gmail.com> wrote:
> > >
> > > Sorry for replying myself but I'm frustrated. Another question I have:
> > Is it
> > > possible to change Polydata point values in a vtkTextureMapToPlane?
> > I've
> > > tried doing:
> > >  vtkTextureMapToPlane *planeMap = vtkTextureMapToPlane::New();
> > > planeMap->GetPolyDataOutput()->SetPoints(vPoints);
> > > Where vPoints is the new array of point values.
> > >
> > > But this doesn't seem to work at all.
> > >
> > >
> > > Godofredo wrote:
> > > >
> > > > Hi. I'm trying to add texture to a region of a 3d polydata. The
> > texture is
> > > > a .jpeg file and the polydata is a triangulated point cloud. I would
> > like
> > > > to know if it's possible to manually assign a region of the .jpeg
> > image to
> > > > each triangle. I don't know if this can be done with the tcoords
> > field.
> > > > Any guidance will be apreciated as I'm a bit stuck. Many thanks in
> > > > andvance
> > > >
> > >
> > > --
> > > View this message in context: http://www.nabble.com/Per-triangle-texturing.-Please-help%21%21-tf4371233.html#a12460175
> >
> > > Sent from the VTK - Users mailing list archive at Nabble.com.
> > >
> > > _______________________________________________
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> > > Please keep messages on-topic. Check the FAQ at:
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> > >
> >
> >
> > --
> > Tim Hutton - http://www.sq3.org.uk
> >
> > Take the Organic Builder challenge -
> > http://www.sq3.org.uk/Evolution/Squirm3/OrganicBuilder/
> >
>
>
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-- 
Wesley D. Turner, Ph.D.
Kitware, Inc.
R&D Engineer
28 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-371-3971 x120
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