[vtkusers] lookupTable

[Phil Cook]

> Message: 1
> Date: Mon, 28 Oct 2002 00:39:59 +0100
> From: Stefan Ulbrich <stevie157 at gmx.net>
> To: vtkusers at public.kitware.com
> Subject: [vtkusers] lookupTable
> 
> hello,
> 
> i want to create a polydata object with several different colors. i've 
> associated a vtkUnsignedCharArray (i also tried float and int) with it 
> using
> 
> scalar-->InsertNextValue(0);
> scalar-->InsertNextValue(1);
> scalar ->InsertNextValue(4);
> pd->GetPointData()->SetScalars(scalar);
> 
> i created a lookuptable
> 
> lup->->SetNumberOfTableValues  (n);
> 
>         lut->SetTableValue(0,1,1,1,1);
>         lut->SetTableValue(1,1,1,1,.5);
>         lut->SetTableValue(2,1,0,0,.75);
>         lut->SetTableValue(3,0,0,1,.25);
>         .....
> 
>  scalars->SetLookupTable (lut);
> 
> but only the points with the scalar value 0 get the right color. the 
> others get the color defined in the last entry of the lookuptable.
> i wrote the object to disk and the values became between 0 and 1.
> 
> what do i have to do, to connect a point to a specific color??
> 
> thank you very much
> 
> stefan
> 
> 

By default, unsigned char scalars will not be mapped through the LUT.
You need to call vtkMapper::SetColorModeToMapScalars() to correct this. 

Also, set the correct scalar range of the LUT. You can do this directly,
or you can call SetScalarRange on the vtkMapper.