Method TransformInput

Rendering/Volume/vtkGPUVolumeRayCastMapper.cxx:731–793

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//------------------------------------------------------------------------------
void vtkGPUVolumeRayCastMapper::TransformInput(int port)
{
  vtkDataSet* dataset = this->TransformedInputs[port];
  if (vtkImageData* clone = vtkImageData::SafeDownCast(dataset))
  {
    if (!dataset)
    {
      clone->SetExtent(0, -1, 0, -1, 0, -1);
      return;
    }

    clone->ShallowCopy(this->GetInput(port));

    // Get the current extents.
    int extents[6];
    clone->GetExtent(extents);

    // Get the current origin and spacing.
    double origin[3], spacing[3];
    clone->GetOrigin(origin);
    clone->GetSpacing(spacing);
    double* direction = clone->GetDirectionMatrix()->GetData();

    // find the location of the min extent
    double blockOrigin[3];
    vtkImageData::TransformContinuousIndexToPhysicalPoint(
      extents[0], extents[2], extents[4], origin, spacing, direction, blockOrigin);

    // make it so that the clone starts with extent 0,0,0
    for (int cc = 0; cc < 3; cc++)
    {
      // Transform the origin and the extents.
      origin[cc] = blockOrigin[cc];
      extents[2 * cc + 1] -= extents[2 * cc];
      extents[2 * cc] = 0;
    }

    clone->SetOrigin(origin);
    clone->SetExtent(extents);
  }
  else if (vtkRectilinearGrid* cloneRGrid = vtkRectilinearGrid::SafeDownCast(dataset))
  {
    if (!dataset)
    {
      cloneRGrid->SetExtent(0, -1, 0, -1, 0, -1);
      return;
    }

    cloneRGrid->ShallowCopy(this->GetInput(port));

    // Get the current extents.
    int extents[6];
    cloneRGrid->GetExtent(extents);

    // Transform the current extent so that it starts at 0, 0, 0
    for (int cc = 0; cc < 3; cc++)
    {
      extents[2 * cc + 1] -= extents[2 * cc];