[vtkusers] scalar type

[Lisa Avila]

The volume mappers in VTK support only unsigned char and unsigned short. 
You can use vtkImageShiftScale to convert to unsigned short.

Lisa


At 04:48 AM 7/14/2004, =?gb2312?B?SmF3Ymlu?= wrote:
>Dear all:
>     I want to do some volume rendering, and the data type is structured 
> points. When
>
>the scalar type is unsigned char, it is ok; but when the scalar type is 
>float, noting is
>
>seen. How can I do this.
>     Thank you very much.
>
>         vtkStructuredPointsReader *reader= vtkStructuredPointsReader::New();
>         //reader->SetFileName("d:/vtkdata/Data/ironprot.vtk");
>         //when the scalar type is unsigned char , it is ok.
>         reader->SetFileName("d:/vtkdata/data/heart.vtk");
>         //when the scalar type is float , noting to be seen.
>         reader->Update();
>
>         float *sr=reader->GetOutput()->GetScalarRange();
>
>         vtkPiecewiseFunction *opacityTransFunc=vtkPiecewiseFunction::New();
>         opacityTransFunc->AddPoint(sr[0],0.0);
>         opacityTransFunc->AddPoint(sr[1],0.2);
>
>         vtkColorTransferFunction 
> *colorTransFunc=vtkColorTransferFunction::New();
>         //blue to red
>         colorTransFunc-> AddHSVPoint  (    sr[0], 0.667, 1.0 ,1.0);//
>         colorTransFunc ->AddHSVPoint  (    sr[1] ,    0 ,1.0, 1.0);//
>         colorTransFunc ->SetColorSpaceToHSV();
>
>         vtkVolumeProperty *volumeProperty= vtkVolumeProperty::New();
>         volumeProperty->SetColor(colorTransFunc);
>         volumeProperty->SetScalarOpacity(opacityTransFunc);
>         volumeProperty->SetInterpolationTypeToNearest();
>
>         vtkVolumeRayCastCompositeFunction *compositeFunction
>                 = vtkVolumeRayCastCompositeFunction::New();
>
>         vtkVolumeRayCastMapper *volumeMapper=vtkVolumeRayCastMapper::New();
>         volumeMapper->SetInput(vtkImageData*)(reader->GetOutput()));
>         volumeMapper->SetVolumeRayCastFunction(compositeFunction);
>
>         vtkVolume *volume=vtkVolume::New();
>         volume->SetMapper( volumeMapper);
>         volume->SetProperty (volumeProperty);
>
>         ren1->AddVolume(volume);
>         renWin->Render();
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