[vtkusers] vtkImage > Data / MapToColors / Cast / Actor..

[Edward Pham]

Hi
I'm trying to create a noisy background using vtkImageData (i've used the 
gaussian distribution to create this)  Its a 2D image along x and z

Below are some details of my code (its not that long, it just seems long but 
its quite straightforward):
I used vtkImageMapToColors and vtkImageCast (because my scalars aer of type 
float not unsigned char)

So all I see is black on my screen...!  :o(
what could i be missing? any ideas..??
thanks in advance...
Ed

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  int offset, iOffset, kOffset, gaussLimit;
  float scalarRange[2] = {VTK_LARGE_FLOAT,-VTK_LARGE_FLOAT};
float x, y, z, gauss, sigmaSquared, sigma;

  NoiseData = vtkImageData::New();
  NoiseFloatArray = vtkFloatArray::New();
  NoiseLookupTable = vtkLookupTable::New();
  ImageMapToColors = vtkImageMapToColors::New();
  ImageCast = vtkImageCast::New();
  ConvertedNoiseData = vtkImageData::New();

NoiseData->SetDimensions( 50, 1, 50 );
NoiseData->SetOrigin(0, 1, 0);
NoiseData->SetSpacing( 1, 1, 1 );
NoiseData->SetScalarType(VTK_FLOAT);

for ( int k=0; k < noiseDimZ; k++ )
{
	z = sigma*Randomize()*gaussLimit;
	kOffset = k*noiseDimZ*noiseDimY;

	for ( int i=0; i < noiseDimX; i++ )
	{
		x = sigma*Randomize()*gaussLimit;        //Randomize generates a random 
number b/w -1 & 1
		gauss = exp(-0.5*((x*x + z*z)/(sigmaSquared)));

		if (gauss<scalarRange[0])
			scalarRange[0] = gauss;
		if (gauss>scalarRange[1])
			scalarRange[1] = gauss;

		offset = i + kOffset;
		NoiseFloatArray->InsertTuple1(  offset, gauss );
	}
}

        NoiseData->GetPointData()->SetScalars( NoiseFloatArray );
	NoiseLookupTable->SetAlphaRange(0,1);
	NoiseLookupTable->SetHueRange(0, 0);
	NoiseLookupTable->SetNumberOfColors(256);
	NoiseLookupTable->SetSaturationRange(0, 1);
	NoiseLookupTable->SetValueRange(0, 1);
	NoiseLookupTable->SetTableRange(scalarRange);
	NoiseLookupTable->Build();

	ImageCast->SetInput( NoiseData );
	ImageCast->SetOutputScalarTypeToUnsignedChar();

	ImageMapToColors->SetInput(ImageCast->GetOutput());
	ImageMapToColors->SetLookupTable(NoiseLookupTable);

//	NoiseData->Modified();
//	ImageMapToColors->Update();
	NoiseActor->SetInput(ImageMapToColors->GetOutput());

	Ren1->AddActor( NoiseActor );
        RenWin->AddRenderer( Ren1 );
       RenWin->SetInteractor(Iren);
       Iren->Initialize();
       Iren->Render();

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