Method CreateMappers

Rendering/VolumeOpenGL2/vtkMultiBlockVolumeMapper.cxx:237–310

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//------------------------------------------------------------------------------
void vtkMultiBlockVolumeMapper::CreateMappers(
  vtkDataObjectTree* input, vtkRenderer* ren, vtkVolume* vol)
{
  // Hierarchical case
  vtkCompositeDataIterator* it = input->NewIterator();
  it->GoToFirstItem();

  bool warnedOnce = false;
  bool allBlocksLoaded = true;
  while (!it->IsDoneWithTraversal())
  {
    vtkImageData* currentIm = vtkImageData::SafeDownCast(it->GetCurrentDataObject());
    vtkRectilinearGrid* currentRect = vtkRectilinearGrid::SafeDownCast(it->GetCurrentDataObject());
    if (!warnedOnce && !currentIm && !currentRect)
    {
      vtkErrorMacro("At least one block in the data object is not of type"
                    " vtkImageData or vtkRectilinearGrid.  These blocks will be ignored.");
      warnedOnce = true;
      it->GoToNextItem();
      continue;
    }

    vtkSmartVolumeMapper* mapper = this->CreateMapper();
    this->Mappers.push_back(mapper);

    if (currentIm)
    {
      vtkNew<vtkImageData> im;
      im->ShallowCopy(currentIm);
      mapper->SetInputData(im);
    }
    else if (currentRect)
    {
      vtkNew<vtkRectilinearGrid> rg;
      rg->ShallowCopy(currentRect);
      mapper->SetInputData(rg);
    }

    // Try allocating GPU memory only while succeeding
    if (allBlocksLoaded)
    {
      vtkOpenGLGPUVolumeRayCastMapper* glMapper =
        vtkOpenGLGPUVolumeRayCastMapper::SafeDownCast(mapper->GetGPUMapper());

      if (glMapper && currentIm)
      {
        vtkImageData* imageInternal = vtkImageData::New();
        imageInternal->ShallowCopy(currentIm);

        glMapper->SetInputData(imageInternal);
        glMapper->SelectScalarArray(this->ArrayName);
        glMapper->SelectScalarArray(this->ArrayId);
        glMapper->SetScalarMode(this->ScalarMode);
        glMapper->SetArrayAccessMode(this->ArrayAccessMode);

        allBlocksLoaded &= glMapper->PreLoadData(ren, vol);
        imageInternal->Delete();
      }