text: /*=========================================================================
  
     Library: iMSTK
  
     Copyright (c) Kitware, Inc. & Center for Modeling, Simulation,
     & Imaging in Medicine, Rensselaer Polytechnic Institute.
  
     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at
  
        http://www.apache.org/licenses/LICENSE-2.0.txt
  
     Unless required by applicable law or agreed to in writing, software
     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
     limitations under the License.
  
  =========================================================================*/
  
  #include "imstkVTKImageDataRenderDelegate.h"
  #include "imstkGeometryUtilities.h"
  #include "imstkImageData.h"
  #include "imstkRenderMaterial.h"
  #include "imstkVisualModel.h"
  
  #include <vtkGPUVolumeRayCastMapper.h>
  #include <vtkImageData.h>
  #include <vtkPointData.h>
  #include <vtkDataArray.h>
  #include <vtkVolume.h>
  #include <vtkTransform.h>
  
  namespace imstk
  {
  VTKImageDataRenderDelegate::VTKImageDataRenderDelegate(std::shared_ptr<VisualModel> visualModel) : VTKVolumeRenderDelegate(visualModel),
      m_scalarArray(nullptr),
      imageDataVtk(nullptr)
  {
      auto imageData = std::dynamic_pointer_cast<ImageData>(m_visualModel->getGeometry());
      m_scalarArray = imageData->getScalars();
  
      // Couple the imstkImageData with vtkImageData
      imageDataVtk = GeometryUtils::coupleVtkImageData(imageData);
  
      // When the image is modified
      queueConnect<Event>(imageData, &ImageData::modified, this, &VTKImageDataRenderDelegate::imageDataModified);
  
      // When the image scalars are modified
      queueConnect<Event>(imageData->getScalars(), &AbstractDataArray::modified, this, &VTKImageDataRenderDelegate::imageScalarsModified);
  
      // Setup mapper
      {
          vtkNew<vtkGPUVolumeRayCastMapper> mapper;
          mapper->SetInputData(imageDataVtk);
          vtkNew<vtkVolume> volume;
          volume->SetMapper(mapper);
          volume->SetUserTransform(m_transform);
          m_mapper = mapper;
          m_actor  = volume;
      }
  
      update();
      updateRenderProperties();
  }
  
  void
  VTKImageDataRenderDelegate::processEvents()
  {
      // This handler chooses and executes the latest event from each respective sender
      std::shared_ptr<ImageData> geom = std::dynamic_pointer_cast<ImageData>(m_visualModel->getGeometry());
  
      // Only use the most recent event from respective sender
      std::list<Command> cmds;
      bool               contains[4] = { false, false, false, false };
      rforeachEvent([&](Command cmd)
          {
              if (cmd.m_event->m_sender == m_visualModel.get() && !contains[0])
              {
                  cmds.push_back(cmd);
                  contains[0] = true;
              }
              else if (cmd.m_event->m_sender == m_material.get() && !contains[1])
              {
                  cmds.push_back(cmd);
                  contains[1] = true;
              }
              else if (cmd.m_event->m_sender == geom.get() && !contains[2])
              {
                  cmds.push_back(cmd);
                  contains[2] = true;
              }
              else if (cmd.m_event->m_sender == geom->getScalars().get() && !contains[3])
              {
                  cmds.push_back(cmd);
                  contains[3] = true;
              }
          });
      // Now do each event in order recieved
      for (std::list<Command>::reverse_iterator i = cmds.rbegin(); i != cmds.rend(); i++)
      {
          i->invoke();
      }
  }
  
  void
  VTKImageDataRenderDelegate::imageDataModified(Event* imstkNotUsed(e))
  {
      auto                                       imageData    = std::static_pointer_cast<ImageData>(m_visualModel->getGeometry());
      vtkSmartPointer<vtkGPUVolumeRayCastMapper> volumeMapper = vtkGPUVolumeRayCastMapper::SafeDownCast(m_mapper);
  
      // If the user swapped scalars on us
      if (m_scalarArray != imageData->getScalars())
      {
          // Update our handle
          m_scalarArray = imageData->getScalars();
  
          // Update vtk data array pointer
          imageDataVtk->GetPointData()->GetScalars()->SetVoidArray(m_scalarArray->getVoidPointer(), m_scalarArray->size(), 1);
  
          // Update information
          // \todo: Can't handle type changes or number of component changes
          const Vec3i& dim = imageData->getDimensions();
          imageDataVtk->SetDimensions(dim.data());
          imageDataVtk->SetExtent(0, dim[0] - 1, 0, dim[1] - 1, 0, dim[2] - 1);
          const Vec3d vtkOrigin = imageData->getOrigin() + imageData->getSpacing() * 0.5;
          imageDataVtk->SetOrigin(vtkOrigin.data());
          imageDataVtk->SetSpacing(imageData->getSpacing().data());
      }
      volumeMapper->GetInput()->Modified();
  }
  
  void
  VTKImageDataRenderDelegate::imageScalarsModified(Event* imstkNotUsed(e))
  {
      auto                                       geometry     = std::static_pointer_cast<ImageData>(m_visualModel->getGeometry());
      vtkSmartPointer<vtkGPUVolumeRayCastMapper> volumeMapper = vtkGPUVolumeRayCastMapper::SafeDownCast(m_mapper);
      m_scalarArray = geometry->getScalars();
  
      // If pointer changed, update the one vtk is viewing
      if (m_scalarArray->getVoidPointer() != imageDataVtk->GetPointData()->GetScalars()->GetVoidPointer(0))
      {
          imageDataVtk->GetPointData()->GetScalars()->SetVoidArray(m_scalarArray->getVoidPointer(), m_scalarArray->size(), 1);
      }
      volumeMapper->GetInput()->Modified();
  }
  } // namespace imstk