[vtkusers] vtkSampleFunction and vtkImageWriter

[David Stocks]

Hello,

I'm trying to generate an image stack from an implicit function.  In 
doing this, I'm trying to feed the output of vtkSampleFunction into 
vtkTIFFWriter as shown below.  When I run this, I get the output:

dstocks at pattiesmuir[~/CIRCE/vtk/Cxx]% ./coneWriter
we want: 3
we got:  3
ERROR: In /tmp/dstocks/VTK/IO/vtkTIFFWriter.cxx, line 463
vtkTIFFWriter (0x8056810): TIFFWriter only accepts unsigned char scalars!

ERROR: In /tmp/dstocks/VTK/IO/vtkTIFFWriter.cxx, line 463
vtkTIFFWriter (0x8056810): TIFFWriter only accepts unsigned char scalars!

[ ... ]

As far as I can see I'm setting the sample function output to the right 
type, but yet something is clearly amiss.  Any suggestions?

Thanks in advance,
David.

#include <iostream>

#include "vtkCone.h"
#include "vtkSampleFunction.h"
#include "vtkTIFFWriter.h"

#define SAMPLE_RANGE_X_MIN -1
#define SAMPLE_RANGE_X_MAX 3
#define SAMPLE_RANGE_Y_MIN -1.25
#define SAMPLE_RANGE_Y_MAX 1.25
#define SAMPLE_RANGE_Z_MIN -1.25
#define SAMPLE_RANGE_Z_MAX 1.25

int main(int argc, char *argv[]) {

   vtkCone *cone = vtkCone::New();
   cone->SetAngle(30);

   vtkSampleFunction *theConeSample = vtkSampleFunction::New();
   theConeSample->SetOutputScalarTypeToUnsignedChar();
   theConeSample->SetImplicitFunction(cone);
   theConeSample->SetModelBounds(SAMPLE_RANGE_X_MIN,
				SAMPLE_RANGE_X_MAX,
				SAMPLE_RANGE_Y_MIN,
				SAMPLE_RANGE_Y_MAX,
				SAMPLE_RANGE_Z_MIN,
				SAMPLE_RANGE_Z_MAX);
   theConeSample->SetSampleDimensions(50, 50, 50);
   theConeSample->ComputeNormalsOff();

   cout << "we want: " << VTK_UNSIGNED_CHAR << endl;
   cout << "we got:  " << theConeSample->GetOutputScalarType() << endl;

   vtkTIFFWriter *writer = vtkTIFFWriter::New();
   writer->SetInput(theConeSample->GetOutput());
   writer->SetFilePrefix("foo");
   writer->Write();

   return(0);
}

-- 
David Stocks
Institute of Perception, Action and Behaviour
School of Informatics, University of Edinburgh
+44 (0)131 651 3436