[vtkusers] vtkStructuredPointsReader and color

[Lisa Avila]

Hello,

unsigned char is a special type that is used directly as a color.  You'll 
need to do mapper->SetColorModeToMapScalars() to get it to map the colors 
through the lookup table.

Lisa



At 10:03 AM 6/5/2002, vtk at le.isac.cnr.it wrote:
>Hi..
>i have an other problem with vtk 4.0 (tcl/tk on linux).
>I have a vtkStructuredPointsReader, and i would like to visualize a 2d 
>images with:
>
>
>********************************************************
>vtkStructuredPointsReader reader
>     reader SetFileName "heart.vtk"
>     reader Update
>
>vtkPlane cutPlane
>     eval cutPlane SetOrigin [[reader GetOutput] GetCenter]
>     cutPlane SetNormal 1 0 0
>
>
>vtkCutter planeCut
>    planeCut  SetInput [reader GetOutput]
>    planeCut SetCutFunction  cutPlane
>
>
># Isosuperficie 2d
>vtkDataSetMapper mapper
>     mapper SetInput [planeCut GetOutput]
>     eval mapper SetScalarRange [[[[reader GetOutput] GetPointData] 
> GetScalars] GetRange]
>
># Linee di livello
>vtkContourFilter contours
>    contours SetInput [planeCut GetOutput]
>    contours GenerateValues 20 0.0 200
>
>#  mapper SetInput [contours GetOutput]
>
>vtkActor cutActor
>    cutActor SetMapper mapper
>
>****************************************************
>
>then i want to visualize a volume, with this code:
>
>************************************************
># Create transfer mapping scalar value to opacity
>vtkPiecewiseFunction opacityTransferFunction
>     opacityTransferFunction AddPoint  20   0.0
>     opacityTransferFunction AddPoint  255  0.2
>
>vtkColorTransferFunction colorTransferFunction
>   colorTransferFunction AddRGBPoint   64 0 1 0
>   colorTransferFunction AddRGBPoint    128 1 0 0
>   colorTransferFunction AddRGBPoint    255 0 0 1
>
>
># The property describes how the data will look
>vtkVolumeProperty volumeProperty
>     volumeProperty SetColor colorTransferFunction
>     volumeProperty SetScalarOpacity opacityTransferFunction
>
># The mapper / ray cast function know how to render the data
>vtkVolumeRayCastCompositeFunction  compositeFunction
>
>vtkVolumeRayCastMapper volumeMapper
>     volumeMapper SetVolumeRayCastFunction compositeFunction
>     volumeMapper SetInput [reader GetOutput]
>
>
># The volume holds the mapper and the property and
># can be used to position/orient the volume
>vtkVolume volume
>     volume SetMapper volumeMapper
>     volume SetProperty volumeProperty
>********************************************************
>
>my header file data is:
>
>
># vtk DataFile Version 2.0
>CT scan data of human heart, courtesy by Henk Mastenbroek RuG
>ASCII
>
>DATASET STRUCTURED_POINTS
>DIMENSIONS    32   32   12
>ORIGIN    0.000   0.000   0.000
>SPACING    1.000   1.000   4.000
>
>POINT_DATA   12288
>SCALARS colors unsigned_char
>LOOKUP_TABLE default
>
>**************************************************
>
>so I visualize the volume with many different color, and the 2d images in 
>the gray scale color.
>If I change SCALARS colors unsigned_char in to SCALAR scalars float, i 
>visualize 2d images in many different color and don't view the volume.
>
>What can i do to visualize all images in many different color???
>
>thanks
>
>
>
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