text: /*=========================================================================
  
    Program:   Visualization Toolkit
    Module:    TestGPURayCastClipping.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.
  
  =========================================================================*/
  // This test covers cropping on volume datasets.
  
  #include <vtkActor.h>
  #include <vtkCamera.h>
  #include <vtkColorTransferFunction.h>
  #include <vtkGPUVolumeRayCastMapper.h>
  #include <vtkImageData.h>
  #include <vtkNew.h>
  #include <vtkPiecewiseFunction.h>
  #include <vtkPlane.h>
  #include <vtkPlaneCollection.h>
  #include <vtkRegressionTestImage.h>
  #include <vtkRenderWindow.h>
  #include <vtkRenderWindowInteractor.h>
  #include <vtkRenderer.h>
  #include <vtkSmartPointer.h>
  #include <vtkTestUtilities.h>
  #include <vtkVolumeProperty.h>
  #include <vtkXMLImageDataReader.h>
  
  int TestGPURayCastClipping(int argc, char *argv[])
  {
    double scalarRange[2];
  
    vtkNew<vtkGPUVolumeRayCastMapper> volumeMapper;
  
    vtkNew<vtkXMLImageDataReader> reader;
    const char* volumeFile = vtkTestUtilities::ExpandDataFileName(
                              argc, argv, "Data/vase_1comp.vti");
  
    reader->SetFileName(volumeFile);
    reader->Update();
    volumeMapper->SetInputConnection(reader->GetOutputPort());
  
    volumeMapper->GetInput()->GetScalarRange(scalarRange);
    volumeMapper->SetBlendModeToComposite();
  
    // Testing prefers image comparison with small images
    vtkNew<vtkRenderWindow> renWin;
    renWin->SetSize(400, 400);
  
    vtkNew<vtkRenderer> ren;
    renWin->AddRenderer(ren.GetPointer());
  
    vtkNew<vtkRenderWindowInteractor> iren;
    iren->SetRenderWindow(renWin.GetPointer());
  
    vtkNew<vtkPiecewiseFunction> scalarOpacity;
    scalarOpacity->AddPoint(scalarRange[0], 0.0);
    scalarOpacity->AddPoint(scalarRange[1], 1.0);
  
    vtkNew<vtkVolumeProperty> volumeProperty;
    volumeProperty->ShadeOff();
    volumeProperty->SetInterpolationType(VTK_LINEAR_INTERPOLATION);
    volumeProperty->SetScalarOpacity(scalarOpacity.GetPointer());
  
    vtkSmartPointer<vtkColorTransferFunction> colorTransferFunction =
      volumeProperty->GetRGBTransferFunction(0);
    colorTransferFunction->RemoveAllPoints();
    colorTransferFunction->AddRGBPoint(scalarRange[0], 0.1, 0.5, 1.0);
    colorTransferFunction->AddRGBPoint(scalarRange[1], 1.0, 0.5, 0.1);
  
    // Test cropping now
    const double* bounds = reader->GetOutput()->GetBounds();
    vtkNew<vtkPlane> clipPlane1;
    clipPlane1->SetOrigin(0.45 * (bounds[0] + bounds[1]), 0.0, 0.0);
    clipPlane1->SetNormal(0.8, 0.0, 0.0);
  
    vtkNew<vtkPlane> clipPlane2;
    clipPlane2->SetOrigin(0.45 * (bounds[0] + bounds[1]),
                          0.35 * (bounds[2] + bounds[3]), 0.0);
    clipPlane2->SetNormal(0.2, -0.2, 0.0);
  
    vtkNew<vtkPlaneCollection> clipPlaneCollection;
    clipPlaneCollection->AddItem(clipPlane1.GetPointer());
    clipPlaneCollection->AddItem(clipPlane2.GetPointer());
    volumeMapper->SetClippingPlanes(clipPlaneCollection.GetPointer());
  
    // Setup volume actor
    vtkNew<vtkVolume> volume;
    volume->SetMapper(volumeMapper.GetPointer());
    volume->SetProperty(volumeProperty.GetPointer());
  
    ren->AddViewProp(volume.GetPointer());
    ren->GetActiveCamera()->Azimuth(-40);
    ren->ResetCamera();
    renWin->Render();
    iren->Initialize();
  
    int retVal = vtkRegressionTestImage( renWin.GetPointer() );
    if( retVal == vtkRegressionTester::DO_INTERACTOR)
    {
      iren->Start();
    }
  
    return !retVal;
  }
  