Method PerVolumeInitialization

Rendering/Volume/vtkFixedPointVolumeRayCastMapper.cxx:1088–1162

This is the initialization that should be done once per volume

// This is the initialization that should be done once per volume
void vtkFixedPointVolumeRayCastMapper::PerVolumeInitialization(vtkRenderer* ren, vtkVolume* vol)
{
  // This is the input of this mapper
  vtkImageData* input = vtkImageData::SafeDownCast(this->GetInput());
  this->PreviousScalars = this->CurrentScalars;

  // make sure that we have scalar input and update the scalar input
  if (input == nullptr)
  {
    vtkErrorMacro(<< "No Input!");
    return;
  }
  else
  {
    vtkAlgorithm* inAlg = this->GetInputAlgorithm();
    inAlg->UpdateWholeExtent();
  }

  int usingCellColors;
  this->CurrentScalars = vtkFixedPointVolumeRayCastMapper::GetScalars(input, this->ScalarMode,
    this->ArrayAccessMode, this->ArrayId, this->ArrayName, usingCellColors);

  if (usingCellColors)
  {
    vtkErrorMacro("Cell Scalars not supported");
    return;
  }

  // Compute some matrices from voxels to view and vice versa based
  // on the whole input
  double inputSpacing[3];
  double inputOrigin[3];
  int inputExtent[6];
  input->GetSpacing(inputSpacing);
  input->GetOrigin(inputOrigin);
  input->GetExtent(inputExtent);

  this->ComputeMatrices(inputOrigin, inputSpacing, inputExtent, ren, vol);

  this->RenderWindow = ren->GetRenderWindow();
  this->Volume = vol;

  // Adjust the sample spacing if necessary
  if (this->LockSampleDistanceToInputSpacing)
  {
    double const dist = this->SpacingAdjustedSampleDistance(inputSpacing, inputExtent);

    // Need to treat interactive renders differently, because if
    // AutoAdjustSampleDistances is on, then we doubled the sample
    // distance
    if (this->AutoAdjustSampleDistances && vol->GetAllocatedRenderTime() < 1.0)
    {
      if (this->SampleDistance / (dist * 2) < 0.999 || this->SampleDistance / (dist * 2) > 1.001)
      {
        this->OldSampleDistance = dist;
        this->SampleDistance = dist * 2;
        this->InteractiveSampleDistance = dist * 2;
      }