[vtkusers] How to use LookupTable correctly?

[Khew Sing Yoong]

Tried it.. doesn't work.. still the same behaviour.. i am guessing it 
might be something to do with the mapper that isn't set correctly???

SY

Paul Tait - OPES wrote:

>My two color code looks like this
>
>	lut = vtkLookupTable::New();
>	lut->SetNumberOfTableValues(2);
>	lut->SetTableValue(0, 0.8, 0.8, 0.8);
>	lut->SetTableValue(1, 0.0, 1.0, 1.0);
>	lut->Build();
>
>-----Original Message-----
>From: vtkusers-bounces+paul=opes.com.au at vtk.org
>[mailto:vtkusers-bounces+paul=opes.com.au at vtk.org] On Behalf Of Khew Sing
>Yoong
>Sent: Friday, 23 June 2006 1:28 AM
>To: vtkusers at vtk.org
>Subject: [vtkusers] How to use LookupTable correctly? 
>
>
>Hi there,
>
>I am fairly new to vtk and I am having problems drawing lines with 
>colours using a lookup table. I am using VTK 5.0.
>
>In a snapshot: create a vtkPolyData, assign 3 points, and connect them 
>with 2 lines in the form of an L shape.
>I want to color the first point Red, second Green, third Blue, hence I 
>assign 0, 1, 2 as scalar values for each point respectively. Then I created
>a lookup table for the PolyDataMapper with 0,1,2 mapping 
>to RGB.
>Connect the pipe and the results weren't as expected. Green never shows up!
>
>Can somebody be kind enough to help me out here a little? Maybe I missed 
>something? Thank you in advance! :)
>
>SY
>
>
>    vtkPolyData * data = vtkPolyData::New();
>    vtkPoints *Points = vtkPoints::New();
>    vtkCellArray *Lines= vtkCellArray::New();
>    vtkIntArray *color = vtkIntArray::New();
>    Points->Allocate(3);
>    Lines->Allocate(2);
>    color->SetName("Color");
>    color->SetNumberOfComponents(1);
>
>    Points->InsertNextPoint(0, 1, 0);
>    Points->InsertNextPoint(0, 0, 0);
>    Points->InsertNextPoint(1, 0, 0);
>    vtkIdType line[2];
>    line[0] = 0;
>    line[1] = 1;
>    Lines->InsertNextCell(2, line);
>    line[0] = 1;
>    line[1] = 2;
>    Lines->InsertNextCell(2, line);
>    color->InsertNextValue(0);
>    color->InsertNextValue(1);
>    color->InsertNextValue(2);
>    data->SetPoints(Points);
>    data->SetLines(Lines);
>    data->GetPointData()->SetScalars(color);
>    data->Squeeze();
>    
>    vtkPolyDataMapper * mapper = vtkPolyDataMapper::New();
>    mapper->SetInput(data);
>    mapper->SetScalarVisibility(1);
>
>    vtkLookupTable * lut = vtkLookupTable::New();
>    lut->SetTableRange(0, 3);
>    lut->SetNumberOfColors(3);
>    lut->Build();
>    lut->SetTableValue(0, 1, 0, 0, 1);
>    lut->SetTableValue(1, 0, 1, 0, 1);
>    lut->SetTableValue(2, 0, 0, 1, 1);
>    
>    mapper->SetLookupTable(lut);
>    mapper->SetScalarModeToUsePointFieldData();
>    mapper->SetColorModeToMapScalars();
>    mapper->SelectColorArray("Color");
>
>    vtkActor * actor = vtkActor::New();
>    actor->SetMapper(mapper);
>    actor->GetProperty()->SetLineWidth(2);
>    ren1->AddActor(actor); _______________________________________________
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