VTK LookupLable or CellData problem?

Development
1

I wanna have reflect CellData colors to the object,but the result is platelike,disperse, and does not have color changes,the vtkScalarBarActor also has this problem.vtkPolyData *data;

  vtkSmartPointer<vtkPolyData> polyData;
  //vtkUnstructuredGrid* unstructuredGrid;
  vtkUnstructuredGrid* unstructuredGrid;
  //vtkUnstructuredGrid *

  QFileInfo info(fname);
  bool knownFileType = true;
  if (info.suffix() == QString(tr("vtk")))
    {

        data = readAnPolyData<vtkPolyDataReader >(fname.toStdString().c_str());

        vtkSmartPointer<vtkUnstructuredGridReader> reader = vtkSmartPointer<vtkUnstructuredGridReader>::New();
        reader->SetFileName(fname.toStdString().c_str());
        reader->Update();
        unstructuredGrid = vtkUnstructuredGrid::SafeDownCast(reader->GetOutput());

        if (unstructuredGrid)
        {

            // 获取标量范围
                double scalarRange[2];
                unstructuredGrid->GetScalarRange(scalarRange);  // 获取数据的标量范围
                std::cout << "Scalar Range: " << scalarRange[0] << ", " << scalarRange[1] << std::endl;

                // 在 unstructuredGrid 上设置活动标量数组
                unstructuredGrid->GetCellData()->SetActiveScalars("p");

                vtkSmartPointer<vtkDataSetMapper> mapper = vtkSmartPointer<vtkDataSetMapper>::New();
                mapper->SetInputData(unstructuredGrid);  // 使用 unstructuredGrid 作为输入

                // 创建查找表 (lookup table)
                vtkSmartPointer<vtkLookupTable> lut = vtkSmartPointer<vtkLookupTable>::New();
                lut->SetNumberOfTableValues(256);  // 设置查找表的颜色数
                lut->SetRange(scalarRange);  // 设置查找表的范围为标量范围
                //lut->SetHueRange(0.667,1.0);
                lut->Build();


                // 配置 mapper 的查找表
                mapper->SetLookupTable(lut);
                mapper->SetScalarRange(scalarRange);
                mapper->SetScalarModeToUseCellData();  // 使用单元格数据进行标量映射

                // 创建 actor 并设置 mapper
                vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
                actor->SetMapper(mapper);

                // 创建 scalar bar (标量条)
                vtkSmartPointer<vtkScalarBarActor> scalarBarActor = vtkSmartPointer<vtkScalarBarActor>::New();
                scalarBarActor->SetLookupTable(mapper->GetLookupTable());  // 同步 mapper 的 lookupTable
                scalarBarActor->SetTitle("Scalar Values");  // 图例标题
                scalarBarActor->SetNumberOfLabels(4);  // 设置显示的刻度标签数
                scalarBarActor->SetMaximumNumberOfColors(256);  // 确保显示多个颜色

                // 添加 actor 和 scalar bar 到渲染器
                ren->AddActor(actor);
                ren->AddActor(scalarBarActor);

                // 重置相机并刷新渲染
                ren->ResetCamera();
                ren->ResetCameraClippingRange();
                ren->Render();
                this->openGLWidget->renderWindow()->Render();