[vtkusers] why the color of actor is white by seting the vtkLookupTable

[朱文武]

Bill, thanks very much !
Here are the all related codes:
vtkSmartPointer<vtkBMPReader> m_read = vtkSmartPointer<vtkBMPReader>::New();
m_read->SetFilePrefix("C:/Data/brain/TCVH_");//
m_read->SetFilePattern("%s%d.bmp"); //
m_read->Allow8BitBMPOn();
m_read->SetDataByteOrderToLittleEndian();
m_read->SetFileNameSliceOffset(5);//
m_read->SetFileNameSliceSpacing(1);//
m_read->SetNumberOfScalarComponents(3);//
m_read->SetDataOrigin(0.0,0.0,0.0);//
m_read->SetDataSpacing(0.167*4,0.167*4,1);//
m_read->SetDataExtent(0,299,0,345,1300,1320);//
m_read->Update();

vtkSmartPointer<vtkDiscreteMarchingCubes> cube =
    vtkSmartPointer<vtkDiscreteMarchingCubes>::New() ;
cube->SetInput((vtkDataObject*) m_read->GetOutput() );
cube->SetValue(0, 111);
cube->SetValue(1, 121);
cube->Update() ;

vtkSmartPointer<vtkDecimatePro>  deci =
vtkSmartPointer<vtkDecimatePro>::New();
deci->SetInputConnection(cube->GetOutputPort());//
deci->SetTargetReduction(0.5); //
deci->PreserveTopologyOn(); //
deci->ReleaseDataFlagOn();

vtkSmartPointer<vtkWindowedSincPolyDataFilter> smoother=
vtkSmartPointer<vtkWindowedSincPolyDataFilter>::New();
smoother->SetInput(deci->GetOutput());
smoother->SetNumberOfIterations(30) ;
smoother->NonManifoldSmoothingOn();
smoother->NormalizeCoordinatesOn();
smoother->GenerateErrorScalarsOn() ;
smoother->Update();

vtkSmartPointer<vtkLookupTable> colorLookupTable=
vtkSmartPointer<vtkLookupTable>::New();

colorLookupTable->SetTableRange(0, 122);
colorLookupTable->SetNumberOfTableValues(123);
colorLookupTable->Build();
for (int i =0; i < 111; i++)
{
    colorLookupTable->SetTableValue(i , i/255.0, i/255.0,i/255.0);
}
colorLookupTable->SetTableValue(111, 1,0,0,1);
for (int j = 112; j <120; j++)
{
    colorLookupTable->SetTableValue(j , j/255.0, j/255.0, j/255.0);

}
colorLookupTable->SetTableValue(121, 0,1,1,1);
colorLookupTable->SetTableValue(122, 0,1,1,1);

vtkSmartPointer<vtkPolyDataNormals> triangleCellNormals =
vtkSmartPointer<vtkPolyDataNormals>::New();
triangleCellNormals->SetInput(smoother->GetOutput());
triangleCellNormals->ComputeCellNormalsOn();
triangleCellNormals->ComputePointNormalsOff();
triangleCellNormals->ConsistencyOn();
triangleCellNormals->AutoOrientNormalsOn();
triangleCellNormals->Update() ;

vtkSmartPointer<vtkPolyDataMapper> mapper =
vtkSmartPointer<vtkPolyDataMapper>::New();
mapper->SetInput(triangleCellNormals->GetOutput()); // #this is better for
vis
mapper->ScalarVisibilityOn() ;//#show colour
mapper->SetScalarRange(colorLookupTable->GetTableRange());
mapper->SetScalarModeToUseCellData() ; //  contains the label eg. 31
//mapper->SetScalarModeToUsePointData() ;//#the smoother error relates to
the verts
mapper->SetLookupTable(colorLookupTable);

vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
actor->SetMapper(mapper);

Waiting for suggestion, thanks in advance !

Wenwu



On Fri, Apr 16, 2010 at 12:01 PM, Bill Lorensen <bill.lorensen at gmail.com>wrote:

> The lookup table and mapper look OK to me. Can you attach the entire
> program if it is not too large?
>
> Bill
>
> On Thu, Apr 15, 2010 at 9:00 PM, 朱文武 <cool.wenwu at gmail.com> wrote:
> > hi all,
> >
> >       I sent the message last night!  However, no one responded ! So, i
> send
> > it again. Please forgive me, if it disrupts you!
> >
> > I use vtkDiscreteMarchingCubes to reconstruct anatomy structure, and use
> the
> > vtkLookupTable to map the color. Now, i design the color map as follows:
> > gray value (111) to red,
> > gray value(121) to blue.
> > Other gray value I don't care.
> >
> > Also, the parameter I set in SetValue() of  vtkDiscreteMarchingCubes is:
> > SetValue(0, 111);
> > SetValue(1, 121);
> >
> > Then i set the lookup table as follows:
> > vtkSmartPointer<vtkLookupTable> colorLookupTable=
> > vtkSmartPointer<vtkLookupTable>::New();
> > colorLookupTable->SetTableRange(0, 122); //
> > colorLookupTable->SetNumberOfTableValues(123);
> > colorLookupTable->Build();
> >
> > for (int i =0; i < 111; i++)
> > {
> >     colorLookupTable->SetTableValue(i , i/255.0, i/255.0,i/255.0); // i
> > don't care this loop
> > }
> > colorLookupTable->SetTableValue(111, 1,0,0,1); // this is essential for
> me
> > for (int j = 112; j <120; j++)
> > {
> >     colorLookupTable->SetTableValue(j , j/255.0, j/255.0, j/255.0); // i
> > don't care this loop
> >
> > }
> > colorLookupTable->SetTableValue(121, 0,0,1,1);
> > colorLookupTable->SetTableValue(122, 0,0,1,1);
> >
> > vtkSmartPointer<vtkPolyDataMapper> mapper =
> > vtkSmartPointer<vtkPolyDataMapper>::New();
> > ...
> > mapper->ScalarVisibilityOn() ;//#show colour
> > mapper->SetScalarRange(colorLookupTable->GetTableRange());
> > mapper->SetScalarModeToUseCellData() ;
> > mapper->SetLookupTable(colorLookupTable);
> >
> > The result of construction is that two structures whose gray value is 111
> > and 121 were reconstructed.
> > However, the color of these actors is the same- white.
> > Ccould anyone tell me why and give some suggestions?
> >
> > Thanks
> > Wenwu
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>



-- 
祝
工作愉快，身体健康！
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