# FixedPointVolumeRayCastMapperCT

VTKExamples/Cxx/VolumeRendering/FixedPointVolumeRayCastMapperCT

### Description

Note

This original source code for this example is here.

### Code

FixedPointVolumeRayCastMapperCT.cxx

    #include <vtkFixedPointVolumeRayCastMapper.h>

    #include <vtkBoxWidget.h>
    #include <vtkCamera.h>
    #include <vtkCommand.h>
    #include <vtkColorTransferFunction.h>
    #include <vtkDICOMImageReader.h>
    #include <vtkImageData.h>
    #include <vtkImageResample.h>
    #include <vtkMetaImageReader.h>
    #include <vtkPiecewiseFunction.h>
    #include <vtkPlanes.h>
    #include <vtkProperty.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkVolume.h>
    #include <vtkVolumeProperty.h>
    #include <vtkXMLImageDataReader.h>
    #include <vtkNamedColors.h>

    #define VTI_FILETYPE 1
    #define MHA_FILETYPE 2

    namespace
    {
    void PrintUsage()
    {
      cout << "Usage: " << endl;
      cout << endl;
      cout << "  FixedPointVolumeRayCastMapperCT <options>" << endl;
      cout << endl;
      cout << "where options may include: " << endl;
      cout << endl;
      cout << "  -DICOM <directory>" << endl;
      cout << "  -VTI <filename>" << endl;
      cout << "  -MHA <filename>" << endl;
      cout << "  -DependentComponents" << endl;
      cout << "  -Clip" << endl;
      cout << "  -MIP <window> <level>" << endl;
      cout << "  -CompositeRamp <window> <level>" << endl;
      cout << "  -CompositeShadeRamp <window> <level>" << endl;
      cout << "  -CT_Skin" << endl;
      cout << "  -CT_Bone" << endl;
      cout << "  -CT_Muscle" << endl;
      cout << "  -FrameRate <rate>" << endl;
      cout << "  -DataReduction <factor>" << endl;
      cout << endl;
      cout << "You must use either the -DICOM option to specify the directory where" << endl;
      cout << "the data is located or the -VTI or -MHA option to specify the path of a .vti file." << endl;
      cout << endl;
      cout << "By default, the program assumes that the file has independent components," << endl;
      cout << "use -DependentComponents to specify that the file has dependent components." << endl;
      cout << endl;
      cout << "Use the -Clip option to display a cube widget for clipping the volume." << endl;
      cout << "Use the -FrameRate option with a desired frame rate (in frames per second)" << endl;
      cout << "which will control the interactive rendering rate." << endl;
      cout << "Use the -DataReduction option with a reduction factor (greater than zero and" << endl;
      cout << "less than one) to reduce the data before rendering." << endl;
      cout << "Use one of the remaining options to specify the blend function" << endl;
      cout << "and transfer functions. The -MIP option utilizes a maximum intensity" << endl;
      cout << "projection method, while the others utilize compositing. The" << endl;
      cout << "-CompositeRamp option is unshaded compositing, while the other" << endl;
      cout << "compositing options employ shading." << endl;
      cout << endl;
      cout << "Note: MIP, CompositeRamp, CompositeShadeRamp, CT_Skin, CT_Bone," << endl;
      cout << "and CT_Muscle are appropriate for DICOM data. MIP, CompositeRamp," << endl;
      cout << "and RGB_Composite are appropriate for RGB data." << endl;
      cout << endl;
      cout << "Example: FixedPointVolumeRayCastMapperCT -DICOM CTNeck -MIP 4096 1024" << endl;
      cout << endl;
    }
    }
    int main(int argc, char *argv[])
    {
      // Parse the parameters

      int count = 1;
      char *dirname = NULL;
      double opacityWindow = 4096;
      double opacityLevel = 2048;
      int blendType = 0;
      int clip = 0;
      double reductionFactor = 1.0;
      double frameRate = 10.0;
      char *fileName=0;
      int fileType=0;

      bool independentComponents=true;

      while ( count < argc )
      {
        if ( !strcmp( argv[count], "?" ) )
        {
          PrintUsage();
          exit(EXIT_SUCCESS);
        }
        else if ( !strcmp( argv[count], "-DICOM" ) )
        {
          size_t size = strlen(argv[count+1])+1;
          dirname = new char[size];
          snprintf( dirname, size, "%s", argv[count+1] );
          count += 2;
        }
        else if ( !strcmp( argv[count], "-VTI" ) )
        {
          size_t size = strlen(argv[count+1])+1;
          fileName = new char[size];
          fileType = VTI_FILETYPE;
          snprintf( fileName, size, "%s", argv[count+1] );
          count += 2;
        }
        else if ( !strcmp( argv[count], "-MHA" ) )
        {
          size_t size = strlen(argv[count+1])+1;
          fileName = new char[size];
          fileType = MHA_FILETYPE;
          snprintf( fileName, size, "%s", argv[count+1] );
          count += 2;
        }
        else if ( !strcmp( argv[count], "-Clip") )
        {
          clip = 1;
          count++;
        }
        else if ( !strcmp( argv[count], "-MIP" ) )
        {
          opacityWindow = atof( argv[count+1] );
          opacityLevel  = atof( argv[count+2] );
          blendType = 0;
          count += 3;
        }
        else if ( !strcmp( argv[count], "-CompositeRamp" ) )
        {
          opacityWindow = atof( argv[count+1] );
          opacityLevel  = atof( argv[count+2] );
          blendType = 1;
          count += 3;
        }
        else if ( !strcmp( argv[count], "-CompositeShadeRamp" ) )
        {
          opacityWindow = atof( argv[count+1] );
          opacityLevel  = atof( argv[count+2] );
          blendType = 2;
          count += 3;
        }
        else if ( !strcmp( argv[count], "-CT_Skin" ) )
        {
          blendType = 3;
          count += 1;
        }
        else if ( !strcmp( argv[count], "-CT_Bone" ) )
        {
          blendType = 4;
          count += 1;
        }
        else if ( !strcmp( argv[count], "-CT_Muscle" ) )
        {
          blendType = 5;
          count += 1;
        }
        else if ( !strcmp( argv[count], "-RGB_Composite" ) )
        {
          blendType = 6;
          count += 1;
        }
        else if ( !strcmp( argv[count], "-FrameRate") )
        {
          frameRate = atof( argv[count+1] );
          if ( frameRate < 0.01 || frameRate > 60.0 )
          {
            cout << "Invalid frame rate - use a number between 0.01 and 60.0" << endl;
            cout << "Using default frame rate of 10 frames per second." << endl;
            frameRate = 10.0;
          }
          count += 2;
        }
        else if ( !strcmp( argv[count], "-ReductionFactor") )
        {
          reductionFactor = atof( argv[count+1] );
          if ( reductionFactor <= 0.0 || reductionFactor >= 1.0 )
          {
            cout << "Invalid reduction factor - use a number between 0 and 1 (exclusive)" << endl;
            cout << "Using the default of no reduction." << endl;
            reductionFactor = 1.0;
          }
          count += 2;
        }
         else if ( !strcmp( argv[count], "-DependentComponents") )
         {
          independentComponents=false;
          count += 1;
         }
        else
        {
          cout << "Unrecognized option: " << argv[count] << endl;
          cout << endl;
          PrintUsage();
          exit(EXIT_FAILURE);
        }
      }

      if ( !dirname && !fileName)
      {
        cout << "Error: you must specify a directory of DICOM data or a .vti file or a .mha!" << endl;
        cout << endl;
        PrintUsage();
        exit(EXIT_FAILURE);
      }

      // Create the renderer, render window and interactor
      vtkSmartPointer<vtkNamedColors> colors =
        vtkSmartPointer<vtkNamedColors>::New();
      vtkRenderer *renderer = vtkRenderer::New();
      vtkRenderWindow *renWin = vtkRenderWindow::New();
      renWin->AddRenderer(renderer);

      // Connect it all. Note that funny arithematic on the
      // SetDesiredUpdateRate - the vtkRenderWindow divides it
      // allocated time across all renderers, and the renderer
      // divides it time across all props. If clip is
      // true then there are two props
      vtkRenderWindowInteractor *iren = vtkRenderWindowInteractor::New();
      iren->SetRenderWindow(renWin);
      iren->SetDesiredUpdateRate(frameRate / (1+clip) );

      iren->GetInteractorStyle()->SetDefaultRenderer(renderer);

      // Read the data
      vtkAlgorithm *reader=0;
      vtkImageData *input=0;
      if(dirname)
      {
        vtkDICOMImageReader *dicomReader = vtkDICOMImageReader::New();
        dicomReader->SetDirectoryName(dirname);
        dicomReader->Update();
        input=dicomReader->GetOutput();
        reader=dicomReader;
      }
      else if ( fileType == VTI_FILETYPE )
      {
        vtkXMLImageDataReader *xmlReader = vtkXMLImageDataReader::New();
        xmlReader->SetFileName(fileName);
        xmlReader->Update();
        input=xmlReader->GetOutput();
        reader=xmlReader;
      }
      else if ( fileType == MHA_FILETYPE )
      {
        vtkMetaImageReader *metaReader = vtkMetaImageReader::New();
        metaReader->SetFileName(fileName);
        metaReader->Update();
        input=metaReader->GetOutput();
        reader=metaReader;
      }
      else
      {
        cout << "Error! Not VTI or MHA!" << endl;
        exit(EXIT_FAILURE);
      }

      // Verify that we actually have a volume
      int dim[3];
      input->GetDimensions(dim);
      if ( dim[0] < 2 ||
           dim[1] < 2 ||
           dim[2] < 2 )
      {
        cout << "Error loading data!" << endl;
        exit(EXIT_FAILURE);
      }

      vtkImageResample *resample = vtkImageResample::New();
      if ( reductionFactor < 1.0 )
      {
        resample->SetInputConnection( reader->GetOutputPort() );
        resample->SetAxisMagnificationFactor(0, reductionFactor);
        resample->SetAxisMagnificationFactor(1, reductionFactor);
        resample->SetAxisMagnificationFactor(2, reductionFactor);
      }

      // Create our volume and mapper
      vtkVolume *volume = vtkVolume::New();
      vtkFixedPointVolumeRayCastMapper *mapper = vtkFixedPointVolumeRayCastMapper::New();

      if ( reductionFactor < 1.0 )
      {
        mapper->SetInputConnection( resample->GetOutputPort() );
      }
      else
      {
        mapper->SetInputConnection( reader->GetOutputPort() );
      }

      // Set the sample distance on the ray to be 1/2 the average spacing
      double spacing[3];
      if ( reductionFactor < 1.0 )
      {
        resample->GetOutput()->GetSpacing(spacing);
      }
      else
      {
        input->GetSpacing(spacing);
      }

    //  mapper->SetSampleDistance( (spacing[0]+spacing[1]+spacing[2])/6.0 );
    //  mapper->SetMaximumImageSampleDistance(10.0);

      // Create our transfer function
      vtkColorTransferFunction *colorFun = vtkColorTransferFunction::New();
      vtkPiecewiseFunction *opacityFun = vtkPiecewiseFunction::New();

      // Create the property and attach the transfer functions
      vtkVolumeProperty *property = vtkVolumeProperty::New();
      property->SetIndependentComponents(independentComponents);
      property->SetColor( colorFun );
      property->SetScalarOpacity( opacityFun );
      property->SetInterpolationTypeToLinear();

      // connect up the volume to the property and the mapper
      volume->SetProperty( property );
      volume->SetMapper( mapper );

      // Depending on the blend type selected as a command line option,
      // adjust the transfer function
      switch ( blendType )
      {
        // MIP
        // Create an opacity ramp from the window and level values.
        // Color is white. Blending is MIP.
        case 0:
          colorFun->AddRGBSegment(0.0, 1.0, 1.0, 1.0, 255.0, 1.0, 1.0, 1.0 );
          opacityFun->AddSegment( opacityLevel - 0.5*opacityWindow, 0.0,
                                  opacityLevel + 0.5*opacityWindow, 1.0 );
          mapper->SetBlendModeToMaximumIntensity();
          break;

        // CompositeRamp
        // Create a ramp from the window and level values. Use compositing
        // without shading. Color is a ramp from black to white.
        case 1:
          colorFun->AddRGBSegment(opacityLevel - 0.5*opacityWindow, 0.0, 0.0, 0.0,
                                  opacityLevel + 0.5*opacityWindow, 1.0, 1.0, 1.0 );
          opacityFun->AddSegment( opacityLevel - 0.5*opacityWindow, 0.0,
                                  opacityLevel + 0.5*opacityWindow, 1.0 );
          mapper->SetBlendModeToComposite();
          property->ShadeOff();
          break;

        // CompositeShadeRamp
        // Create a ramp from the window and level values. Use compositing
        // with shading. Color is white.
        case 2:
          colorFun->AddRGBSegment(0.0, 1.0, 1.0, 1.0, 255.0, 1.0, 1.0, 1.0 );
          opacityFun->AddSegment( opacityLevel - 0.5*opacityWindow, 0.0,
                                  opacityLevel + 0.5*opacityWindow, 1.0 );
          mapper->SetBlendModeToComposite();
          property->ShadeOn();
          break;

        // CT_Skin
        // Use compositing and functions set to highlight skin in CT data
        // Not for use on RGB data
        case 3:
          colorFun->AddRGBPoint( -3024, 0, 0, 0, 0.5, 0.0 );
          colorFun->AddRGBPoint( -1000, .62, .36, .18, 0.5, 0.0 );
          colorFun->AddRGBPoint( -500, .88, .60, .29, 0.33, 0.45 );
          colorFun->AddRGBPoint( 3071, .83, .66, 1, 0.5, 0.0 );

          opacityFun->AddPoint(-3024, 0, 0.5, 0.0 );
          opacityFun->AddPoint(-1000, 0, 0.5, 0.0 );
          opacityFun->AddPoint(-500, 1.0, 0.33, 0.45 );
          opacityFun->AddPoint(3071, 1.0, 0.5, 0.0);

          mapper->SetBlendModeToComposite();
          property->ShadeOn();
          property->SetAmbient(0.1);
          property->SetDiffuse(0.9);
          property->SetSpecular(0.2);
          property->SetSpecularPower(10.0);
          property->SetScalarOpacityUnitDistance(0.8919);
          break;

        // CT_Bone
        // Use compositing and functions set to highlight bone in CT data
        // Not for use on RGB data
        case 4:
          colorFun->AddRGBPoint( -3024, 0, 0, 0, 0.5, 0.0 );
          colorFun->AddRGBPoint( -16, 0.73, 0.25, 0.30, 0.49, .61 );
          colorFun->AddRGBPoint( 641, .90, .82, .56, .5, 0.0 );
          colorFun->AddRGBPoint( 3071, 1, 1, 1, .5, 0.0 );

          opacityFun->AddPoint(-3024, 0, 0.5, 0.0 );
          opacityFun->AddPoint(-16, 0, .49, .61 );
          opacityFun->AddPoint(641, .72, .5, 0.0 );
          opacityFun->AddPoint(3071, .71, 0.5, 0.0);

          mapper->SetBlendModeToComposite();
          property->ShadeOn();
          property->SetAmbient(0.1);
          property->SetDiffuse(0.9);
          property->SetSpecular(0.2);
          property->SetSpecularPower(10.0);
          property->SetScalarOpacityUnitDistance(0.8919);
          break;

        // CT_Muscle
        // Use compositing and functions set to highlight muscle in CT data
        // Not for use on RGB data
        case 5:
          colorFun->AddRGBPoint( -3024, 0, 0, 0, 0.5, 0.0 );
          colorFun->AddRGBPoint( -155, .55, .25, .15, 0.5, .92 );
          colorFun->AddRGBPoint( 217, .88, .60, .29, 0.33, 0.45 );
          colorFun->AddRGBPoint( 420, 1, .94, .95, 0.5, 0.0 );
          colorFun->AddRGBPoint( 3071, .83, .66, 1, 0.5, 0.0 );

          opacityFun->AddPoint(-3024, 0, 0.5, 0.0 );
          opacityFun->AddPoint(-155, 0, 0.5, 0.92 );
          opacityFun->AddPoint(217, .68, 0.33, 0.45 );
          opacityFun->AddPoint(420,.83, 0.5, 0.0);
          opacityFun->AddPoint(3071, .80, 0.5, 0.0);

          mapper->SetBlendModeToComposite();
          property->ShadeOn();
          property->SetAmbient(0.1);
          property->SetDiffuse(0.9);
          property->SetSpecular(0.2);
          property->SetSpecularPower(10.0);
          property->SetScalarOpacityUnitDistance(0.8919);
          break;

        // RGB_Composite
        // Use compositing and functions set to highlight red/green/blue regions
        // in RGB data. Not for use on single component data
        case 6:
          opacityFun->AddPoint(0, 0.0);
          opacityFun->AddPoint(5.0, 0.0);
          opacityFun->AddPoint(30.0, 0.05);
          opacityFun->AddPoint(31.0, 0.0);
          opacityFun->AddPoint(90.0, 0.0);
          opacityFun->AddPoint(100.0, 0.3);
          opacityFun->AddPoint(110.0, 0.0);
          opacityFun->AddPoint(190.0, 0.0);
          opacityFun->AddPoint(200.0, 0.4);
          opacityFun->AddPoint(210.0, 0.0);
          opacityFun->AddPoint(245.0, 0.0);
          opacityFun->AddPoint(255.0, 0.5);

          mapper->SetBlendModeToComposite();
          property->ShadeOff();
          property->SetScalarOpacityUnitDistance(1.0);
          break;
        default:
           vtkGenericWarningMacro("Unknown blend type.");
           break;
      }

      // Set the default window size
      renWin->SetSize(600,600);
      renWin->Render();

      // Add the volume to the scene
      renderer->AddVolume( volume );

      renderer->ResetCamera();
      renderer->SetBackground(colors->GetColor3d("SlateGray").GetData());

      // interact with data
      renWin->Render();

      iren->Start();

      opacityFun->Delete();
      colorFun->Delete();
      property->Delete();

      volume->Delete();
      mapper->Delete();
      reader->Delete();
      resample->Delete();
      renderer->Delete();
      renWin->Delete();
      iren->Delete();

      return EXIT_SUCCESS;;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(FixedPointVolumeRayCastMapperCT)

    find_package(VTK REQUIRED)
    include(${VTK_USE_FILE})

    add_executable(FixedPointVolumeRayCastMapperCT MACOSX_BUNDLE FixedPointVolumeRayCastMapperCT.cxx )

    target_link_libraries(FixedPointVolumeRayCastMapperCT ${VTK_LIBRARIES})

### Download and Build FixedPointVolumeRayCastMapperCT

Click here to download FixedPointVolumeRayCastMapperCT and its CMakeLists.txt file. Once the tarball FixedPointVolumeRayCastMapperCT.tar has been downloaded and extracted,

    cd FixedPointVolumeRayCastMapperCT/build

If VTK is installed:

    cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

    cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

    make

and run it:

    ./FixedPointVolumeRayCastMapperCT

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.