[vtkusers] Texture mapping

[Remo Ziegler]

Hi David,

thanks a lot for your help. Do you know how I can map one 3D-point on several texture-points? The
problem is, that every triangle is stored independently from the other in the texture file, so
that a 3Dpoint can be mapped on several different positions in the texture file.

Thanks a lot for your help again!!

Greets .... Remo

David Gobbi wrote:

> Hi Remo,
>
> It's about the same in VTK.  In a situation where you already have
> the vertices & texture coords, you can build a vtkPolyData like this:
>
> points = vtkPoints::New();
> points->InsertNextPoint(x,y,z)  // repeat for all points
> ...
>
> polys = vtkCellArray::New();
> polys->InsertNextCell(n);       // n is number of points in polygon
> polys->InsertCellPoint(i);      // i is index into above 'points' list
> polys->InsertCellPoint(j);      // etc. for each point in polygon
> ...
> polys->InsertNextCell(m);       // next polygon
> ...
>
> tcoords = vtkTCoords::New();
> tcoords.InsertNextTCoord(tx,ty,0.0); // one tcoord per point
> ...
>
> data = vtkPolyData::New();
> data->SetPoints(points);
> data->SetPolys(polys);
> data->GetPointData()->SetTCoords(tcoords);
>
> Done!  If you want to set normals for the points, you do it
> the same way as for the TCoords.
>
>  - David
>
> --
>   David Gobbi, MSc                       dgobbi at irus.rri.ca
>   Advanced Imaging Research Group
>   Robarts Research Institute, University of Western Ontario
>
> On Fri, 29 Jun 2001, Remo Ziegler wrote:
>
> > Hi,
> >
> > I have a vtkPolyData object describing the polygonal  model and a
> > bmp-File to describe the texture for it. Since the texture file has a
> > certain structure, I want to map every triangle of vtkPolyData to a
> > triangle in the bmp-file describing the texture.
> > In OpenGL I would use the glTextCoord2f(..., ....); glVertex3f(...,
> > ...., ....); construction ... is there any similar stuff in vtk?
> >
> > Thanks for your help! Have a nice weekend !!
> >
> > Greets .... Remo
> >
> >
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