Method UpdateColorTable

Rendering/Volume/vtkFixedPointVolumeRayCastMapper.cxx:2800–3147

}

int vtkFixedPointVolumeRayCastMapper::UpdateColorTable(vtkVolume* vol)
{
  int needToUpdate = 0;

  // Get the image data
  vtkImageData* input = vtkImageData::SafeDownCast(this->GetInput());

  // Has the data itself changed?
  if (input != this->SavedParametersInput || this->CurrentScalars != this->PreviousScalars ||
    input->GetMTime() > this->SavedParametersMTime.GetMTime())
  {
    needToUpdate = 1;
  }

  // What is the blending mode?
  int blendMode = this->GetBlendMode();
  if (blendMode != this->SavedBlendMode)
  {
    needToUpdate = 1;

    if (this->GetBlendMode() == vtkVolumeMapper::MINIMUM_INTENSITY_BLEND)
    {
      this->FlipMIPComparison = 1;
    }
    else
    {
      this->FlipMIPComparison = 0;
    }
  }

  // How many components?
  int components = this->CurrentScalars->GetNumberOfComponents();

  // Has the sample distance changed?
  if (this->SavedSampleDistance != this->SampleDistance)
  {
    needToUpdate = 1;
  }

  vtkColorTransferFunction* rgbFunc[4];
  vtkPiecewiseFunction* grayFunc[4];
  vtkPiecewiseFunction* scalarOpacityFunc[4];
  vtkPiecewiseFunction* gradientOpacityFunc[4];
  int colorChannels[4];
  float scalarOpacityDistance[4];

  int c;

  for (c = 0; c < ((vol->GetProperty()->GetIndependentComponents()) ? (components) : (1)); c++)
  {
    colorChannels[c] = vol->GetProperty()->GetColorChannels(c);
    if (colorChannels[c] == 1)
    {
      rgbFunc[c] = nullptr;
      grayFunc[c] = vol->GetProperty()->GetGrayTransferFunction(c);
    }
    else
    {