VTK Scenelight vs Headlight, CPU vs GPU

/*=========================================================================

  Program:   Visualization Toolkit
  Module:    GPURenderDemo.cxx

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
// VTK includes
#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 "vtkSmartVolumeMapper.h"

#include "vtkLight.h"
#include "vtkLightCollection.h"

#include <array>

#define VTI_FILETYPE 1
#define MHA_FILETYPE 2

// Callback for moving the planes from the box widget to the mapper
class vtkBoxWidgetCallback : public vtkCommand
{
public:
  static vtkBoxWidgetCallback *New()
    { return new vtkBoxWidgetCallback; }
  void Execute(vtkObject *caller, unsigned long, void*) override
  {
      vtkBoxWidget *widget = reinterpret_cast<vtkBoxWidget*>(caller);
      if (this->Mapper)
      {
        vtkPlanes *planes = vtkPlanes::New();
        widget->GetPlanes(planes);
        this->Mapper->SetClippingPlanes(planes);
        planes->Delete();
      }
  }
  void SetMapper(vtkSmartVolumeMapper* m)
    { this->Mapper = m; }

protected:
  vtkBoxWidgetCallback()
    { this->Mapper = nullptr; }

  vtkSmartVolumeMapper *Mapper;
};

void PrintUsage()
{
  cout << "Usage: " << endl;
  cout << endl;
  cout << "  GPURenderDemo <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: GPURenderDemo -DICOM CTNeck -MIP 4096 1024" << endl;
  cout << endl;
}

int main(int argc, char *argv[])
{
  // Parse the parameters

  int count = 1;
  char *dirname = nullptr;
  double opacityWindow = 4096;
  double opacityLevel = 2048;
  int blendType = 0;
  int clip = 0;
  double reductionFactor = 1.0;
  double frameRate = 10.0;
  char *fileName=nullptr;
  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
  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=nullptr;
  vtkImageData *input=nullptr;
  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);
  }


  // reset the volume's origin to be in the centre of the data =====
  // (makes it easier to manually set up the camera, below)
  std::array<int, 6> extent;
  input->GetExtent(extent.data());

  std::array<double, 3> spacingArray;
  input->GetSpacing(spacingArray.data());

  std::array<double, 3> volumeCentre;

  for (auto &volumeCentreElem : volumeCentre)
  {
      auto i = &volumeCentreElem - &volumeCentre[0];
      volumeCentreElem = spacingArray[i] * -0.5 * (extent[i*2] + extent[(i*2)+1]);
  }

  input->SetOrigin(volumeCentre.data());
  // end of centring the volume ==========

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

  // Add a box widget if the clip option was selected
  vtkBoxWidget *box = vtkBoxWidget::New();
  if (clip)
  {
    box->SetInteractor(iren);
    box->SetPlaceFactor(1.01);
    if ( reductionFactor < 1.0 )
    {
      box->SetInputConnection(resample->GetOutputPort());
    }
    else
    {
      box->SetInputData(input);
    }

    box->SetDefaultRenderer(renderer);
    box->InsideOutOn();
    box->PlaceWidget();
    vtkBoxWidgetCallback *callback = vtkBoxWidgetCallback::New();
    callback->SetMapper(mapper);
    box->AddObserver(vtkCommand::InteractionEvent, callback);
    callback->Delete();
    box->EnabledOn();
    box->GetSelectedFaceProperty()->SetOpacity(0.0);
  }

  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;
  }

  // orient the volume
  volume->SetOrientation(0.0, 90.0, -90.0);

  // pick GPU or CPU rendering in the volume mapper
  mapper->SetRequestedRenderModeToGPU();
  //mapper->SetRequestedRenderModeToRayCast();

  // These are the setting for the head data
  auto light = vtkLight::New();
  light->SetLightTypeToSceneLight();
  //light->SetLightTypeToHeadlight();
  light->SetPosition(0.0, 0.0, -400.0);
  light->SetFocalPoint(0.0, 0.0, 0.0);

  // These are the common lighting settings
  renderer->SetLightFollowCamera(false);
  renderer->AddLight(light);

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

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

  renderer->ResetCamera();

  auto camera = renderer->GetActiveCamera();

  // These are the settings for the head data
  camera->SetPosition(200.0, 200.0, -400.0);
  camera->SetFocalPoint(0.0, 0.0, 0.0);
  camera->SetViewUp(0.0, 1.0, 0.0);
  camera->SetClippingRange(0.1, 1000.0);

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

  iren->Start();

  auto lightCollection = renderer->GetLights();
  lightCollection->InitTraversal();
  auto lightFromCollection = lightCollection->GetNextItem();

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

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

  return 0;
}