[vtkusers] Create a color map using polyData in VTK

[Bill Lorensen]

Change
 mapper->ScalarVisibilityOff();
to
 mapper->ScalarVisibilityOn();

When ScalarVisibility is off, the color of the actor is used. If it is
On, the scalar data mapped through the lookup table will be used.


On Fri, Feb 3, 2012 at 2:19 AM, Gishara Indeewarie <gish.777 at gmail.com> wrote:
> Hi all,
>
> I have a set of points (x,y,z) and the values of each point. I have created
> a surface according to the following example.
> http://www.vtk.org/Wiki/VTK/Examples/Cxx/Filters/SurfaceFromUnorganizedPoints
>
> And I want to create a color map by giving colors to each point according to
> the value of each point.
> My problem is that I can't see the color map in my example. All I see is the
> surface with a plain color.
> The code is as below:
>
> vtkPoints *points = newPts;//ReadCFDData2();
> vtkSmartPointer<vtkPolyData> polydata = vtkSmartPointer<vtkPolyData>::New();
>   polydata->SetPoints(points);
>
>   vtkSmartPointer<vtkDoubleArray> weights =
> vtkSmartPointer<vtkDoubleArray>::New();
>   weights->SetNumberOfValues(PoValues.GetSize());
>   for(int i=0; i< PoValues.GetSize();i++){
>   weights->SetValue(i, PoValues[i]);
>   }
>   polydata->GetPointData()->SetScalars(weights);
>
>   vtkSmartPointer<vtkVertexGlyphFilter> glyphFilter =
>     vtkSmartPointer<vtkVertexGlyphFilter>::New();
> #if VTK_MAJOR_VERSION <= 5
>   glyphFilter->SetInputConnection(polydata->GetProducerPort());
> #else
>   glyphFilter->SetInputData(polydata);
> #endif
>   glyphFilter->Update();
>
>   // Create a plane to cut
>   vtkSmartPointer<vtkPlane> plane =
>     vtkSmartPointer<vtkPlane>::New();
>   plane->SetOrigin(polydata->GetCenter());
>   plane->SetNormal(1,1,1);
>
>
>   // Construct the surface and create isosurface.
>   vtkSmartPointer<vtkSurfaceReconstructionFilter> surf =
>     vtkSmartPointer<vtkSurfaceReconstructionFilter>::New();
>
>   surf->SetInput(polydata);
>  //
>   vtkSmartPointer<vtkContourFilter> cf =
>  vtkSmartPointer<vtkContourFilter>::New();
>   cf->SetInputConnection(surf->GetOutputPort());
>
>    // Create the color map
>   vtkSmartPointer<vtkLookupTable> colorLookupTable =
> vtkSmartPointer<vtkLookupTable>::New();
>   colorLookupTable->SetNumberOfColors(64);
>   colorLookupTable->SetHueRange( 0.0,0.667);
>   colorLookupTable->SetTableRange(0,3);
>   colorLookupTable->Build();
>
>   // Create a mapper and actor
>   vtkSmartPointer<vtkPolyDataMapper> mapper =
> vtkSmartPointer<vtkPolyDataMapper>::New();
>
> mapper->SetInputConnection(/*reverse->GetOutputPort()*/cf->GetOutputPort());
>   mapper->ScalarVisibilityOff();
>   mapper->SetLookupTable(colorLookupTable);
>
>   vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
>    actor->GetProperty()->SetColor(1.0, 0.8941, 0.7686); // bisque
>   actor->SetMapper(mapper);
>
>   //Create a renderer, render window, and interactor
>   vtkSmartPointer<vtkRenderer> renderer
> = vtkSmartPointer<vtkRenderer>::New();
>   vtkSmartPointer<vtkRenderWindow> renderWindow
> = vtkSmartPointer<vtkRenderWindow>::New();
>   renderWindow->AddRenderer(renderer);
>   vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor
> = vtkSmartPointer<vtkRenderWindowInteractor>::New();
>   renderWindowInteractor->SetRenderWindow(renderWindow);
>
>   //Add the actor to the scene
>   renderer->AddActor(actor);
>   renderer->SetBackground(.3, .6, .3); // Background color green
>
>   //Render and interact
>   renderWindow->Render();
>   renderWindowInteractor->Start();
>
> Please explain me where I have gone wrong. Thanks a lot.
>
> --
> Gish
>
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