Function Update

Rendering/VolumeOpenGL2/vtkVolumeMask.h:55–256

--------------------------------------------------------------------------

  //--------------------------------------------------------------------------
  void Update(vtkRenderer* ren, vtkImageData* input, int cellFlag, int textureExtent[6],
    int scalarMode, int arrayAccessMode, int arrayId, const char* arrayName,
    vtkIdType maxMemoryInBytes)
  {
    bool needUpdate = false;
    bool modified = false;

    if (!this->Texture)
    {
      this->Texture = vtkTextureObject::New();
      needUpdate = true;
    }

    vtkOpenGLRenderWindow* renWin = vtkOpenGLRenderWindow::SafeDownCast(ren->GetRenderWindow());
    auto ostate = renWin->GetState();
    this->Texture->SetContext(renWin);

    if (!this->Texture->GetHandle())
    {
      needUpdate = true;
    }

    int obsolete = needUpdate || !this->Loaded || input->GetMTime() > this->BuildTime;
    if (!obsolete)
    {
      obsolete = cellFlag != this->LoadedCellFlag;
      int i = 0;
      while (!obsolete && i < 6)
      {
        obsolete = obsolete || this->LoadedExtent[i] > textureExtent[i];
        ++i;
        obsolete = obsolete || this->LoadedExtent[i] < textureExtent[i];
        ++i;
      }
    }

    if (obsolete)
    {
      this->Loaded = false;
      int dim[3];
      input->GetDimensions(dim);

      vtkDataArray* scalars = vtkAbstractMapper::GetScalars(
        input, scalarMode, arrayAccessMode, arrayId, arrayName, this->LoadedCellFlag);

      // DON'T USE GetScalarType() or GetNumberOfScalarComponents() on
      // ImageData as it deals only with point data...
      int scalarType = scalars->GetDataType();
      if (scalarType != VTK_UNSIGNED_CHAR)
      {
        std::cout << "Mask should be VTK_UNSIGNED_CHAR." << std::endl;
      }
      if (scalars->GetNumberOfComponents() != 1)
      {
        std::cout << "Mask should be a one-component scalar field." << std::endl;
      }

      GLint internalFormat = GL_R8;