[vtkusers] rendering voxels from Java

[kent myers]

I am attempting to display a 3D voxel array from a java application, by
following the example given at

http://vtk.1045678.n5.nabble.com/Visualizing-populated-voxels-td4385698.html

I have a 3d short[][][] array containing the material index for each cell of
a 3D voxel array.  My understanding is that I need to convert this to a 1
dimensional array and pass it to a vtkShortArray.  The java code is shown
below.  I think I have made the correct substitutions of java methods for
C++ methods, but I do not know where to find the constants
VTK_UNSIGNED_CHAR, FIELD_ASSOCIATION_CELLS and SCALARS. Also, I don't
understand how to use the vtkInformation object that is needed for the
vtkImageData object to SetScalarType().

Can anyone help or point me to a java example?

Thanks,
Kent


	public void showExternal(SimExternal external) {
		short[][][] voxelData = external.matrixData.voxelMatrix;
		
		int dimX = voxelData.length;
		int dimY = voxelData[0].length;
		int dimZ = voxelData[0][0].length;
		
		double[] values = external.getValues();
		double voxX = values[3];
		double voxY = values[4];
		double voxZ = values[5];
		
		double minX = 0.0;
		double minY = 0.0;
		double minZ = 0.0;
		
		if(dimZ >= 4) {
			int numSamples = dimX * dimY * dimZ;
			short[] sampleGrid = new short[numSamples];
			for(int i=0, l=0; i<dimX; i++) {
				for(int j=0; i<dimY; j++) {
					for(int k=0; k<dimZ; k++) {
						sampleGrid[l++] = voxelData[i][j][k];
					}
				}
			}
			
		  vtkShortArray sampleData = new vtkShortArray();
		  sampleData.SetJavaArray(sampleGrid);
		  sampleData.SetNumberOfComponents( 1 );
		  sampleData.SetNumberOfTuples( numSamples );
		  sampleData.SetName( "values" );


		  // Set up sampled data space
		  vtkImageData sampledSpace = new vtkImageData();
		  sampledSpace.SetDimensions( dimX, dimY, dimZ );
		  vtkInformation info = new vtkInformation();  // ???
		  
		  sampledSpace.SetScalarType(3, info);  // VTK_UNSIGNED_CHAR = 3
		 
		  sampledSpace.GetPointData().SetScalars( sampleData );
		  sampledSpace.SetSpacing( voxX, voxY, voxZ );  // set dimensions of a
voxel
		  sampledSpace.SetOrigin( (double)minX,
		                           (double)minY,
		                           (double)minZ );       // set lower left corner
location

		  vtkThreshold threshold = new vtkThreshold();
		  threshold.SetInputData(sampledSpace);
		  threshold.SetInputArrayToProcess(0,0,0,1,0);  
// FieldAssociations.FIELD_ASSOCIATION_CELLS = 1, AttributeTypes.SCALARS = 0
		  threshold.ThresholdBetween(5,100);
		  threshold.Update();

		  vtkGeometryFilter geomFilter = new vtkGeometryFilter();
		  geomFilter.SetInputData(threshold.GetOutput());
		  geomFilter.Update();

		  // Create mapper and actor, and add to renderer
		  vtkPolyDataMapper voxelMapper = new vtkPolyDataMapper();
		  voxelMapper.SetInputData( geomFilter.GetOutput() );
		  //voxelMapper->SetScalarRange(5,100);
		  voxelMapper.SetScalarModeToUseCellData();
		  //voxelMapper->SetColorModeToMapScalars();

			SimVisualDocumentVTK doc = ((SimVisualDocumentVTK) document);
		  vtkActor impGeoActor = doc.getElementFaceActor();
		  impGeoActor.SetMapper( voxelMapper );
		  
		  //impGeoActor->GetProperty()->SetColor( 1.0, 0, 0 );
		  //impGeoActor->GetProperty()->SetOpacity( alpha );

//		  int actorId = addActor( impGeoActor );

//		  voxelMapper->Delete();
//		  geomFilter->Delete();
//		  threshold->Delete();
//		  sampledSpace->Delete();
//		  sampleData->Delete();

//		  return actorId;

		}
	}








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