c++ - Visualization Toolkit - 如何读取和渲染多个对象？

Question

我正在尝试使用 vtk 读取和呈现一个目录中的多个文件(当它们组合在一起时形成一个对象)。但到目前为止，我收到以下错误:

ERROR: In D:\VTK\VTK-src\IO\XML\vtkXMLReader.cxx, line 283
vtkXMLPolyDataReader (00D1B560): Error opening file D:\3d models\Dist\.

ERROR: In D:\VTK\VTK-src\Common\ExecutionModel\vtkExecutive.cxx, line 782
vtkCompositeDataPipeline (00CC2078): Algorithm
vtkXMLPolyDataReader(00D1B560) returned failure for request: vtkInformation
(00D20688)
  Debug: Off
  Modified Time: 8721
  Reference Count: 1
  Registered Events: (none)
  Request: REQUEST_DATA
  FORWARD_DIRECTION: 0
  ALGORITHM_AFTER_FORWARD: 1
  FROM_OUTPUT_PORT: 0 

到目前为止，我尝试的是只读取 1 个文件而不是多个文件，但我仍然出现上面提到的错误。

这是我正在编写的代码:

int main(int argc, char *argv[])
{
  std::string directoryName = "D:\\3d models\\Dist\\" ;

  vtkSmartPointer<vtkDirectory> directory = vtkSmartPointer<vtkDirectory>::New();
  int opened = directory->Open(directoryName.c_str());

  if(!opened)
  {
    std::cout << "No es posible abrir este directorio!" << std::endl;
    return EXIT_FAILURE;
  }

  int numberOfFiles = directory->GetNumberOfFiles();
  std::cout << "NUmero de archivos: " << numberOfFiles << std::endl;

  for (int i = 0; i < numberOfFiles; i++)
  {
    std::string fileString = directoryName;
    ////fileString += "/";
    fileString += directory->GetFile(i);

    std::string ext = vtksys::SystemTools::GetFilenameLastExtension(fileString);
    std::cout << fileString.c_str() << " extension: " << ext << std::endl;

    std::string name = vtksys::SystemTools::GetFilenameWithoutLastExtension(fileString);    
    std::cout << "nombre: " << name << std::endl;

    const char*cstr = fileString.c_str();
    std::cout << cstr << endl;

        vtkSmartPointer<vtkXMLPolyDataReader> reader =
            vtkSmartPointer<vtkXMLPolyDataReader>::New();
        reader->SetFileName(cstr);
        reader->Update();
        reader->GetOutput();

        vtkSmartPointer<vtkTransform> transform =
            vtkSmartPointer<vtkTransform>::New();
        transform->Scale(.005, .005, .005);

        vtkSmartPointer<vtkTransformFilter> transformFilter =
            vtkSmartPointer<vtkTransformFilter>::New();
        transformFilter->SetInputConnection(reader->GetOutputPort());
        transformFilter->SetTransform(transform);

        // Visualizar
        vtkSmartPointer<vtkPolyDataMapper> mapper =
            vtkSmartPointer<vtkPolyDataMapper>::New();
        mapper->SetInputConnection(transformFilter->GetOutputPort());

        vtkSmartPointer<vtkActor> actor =
            vtkSmartPointer<vtkActor>::New();
        actor->SetPosition(1.1, .5, .1);
        actor->SetMapper(mapper);

        vtkSmartPointer<vtkOpenVRRenderer> renderer =
            vtkSmartPointer<vtkOpenVRRenderer>::New();
        vtkSmartPointer<vtkOpenVRRenderWindow> renderWindow =
            vtkSmartPointer<vtkOpenVRRenderWindow>::New();
        renderWindow->AddRenderer(renderer);
        vtkSmartPointer<vtkOpenVRRenderWindowInteractor> renderWindowInteractor =
            vtkSmartPointer<vtkOpenVRRenderWindowInteractor>::New();
        renderWindowInteractor->SetRenderWindow(renderWindow);

        vtkNew<vtkOpenVRCamera> cam;
        renderer->SetActiveCamera(cam);

        renderer->AddActor(actor);
        renderer->SetBackground(.2, .3, .4);

        renderWindow->Render();
        renderWindowInteractor->Start();

  }

  return EXIT_SUCCESS;
}

我错过了什么？我已经尝试过不同类型的文件，但我仍然无法使用此方法读取和呈现任何内容。

Answer 1

当您列出文件夹中的文件时，第一个条目似乎是“.”。 (这很正常)，因此您尝试打开的文件路径是“D:\3d models\Dist\”。它不是 vtkXMLPolyDataReader 的有效文件。

您应该只尝试打开用 vtkXMLPolyDataWriter 编写的 vtk 文件。例如，通过检查扩展名是“.vtp”(或您用来保存包含 vtkPolyData 模型的文件的任何扩展名)。

检查循环第一部分中的扩展:

for (int i = 0; i < numberOfFiles; i++)
  {
    std::string fileString = directoryName;
    ////fileString += "/";
    fileString += directory->GetFile(i);

    std::string ext = vtksys::SystemTools::GetFilenameLastExtension(fileString);
    std::cout << fileString.c_str() << " extension: " << ext << std::endl;

    // add this line here to skip "." and "..", also fix the extension if not .xml
    if (ext.find(".vtp") == std::string::npos) continue;

    (...)

我还怀疑您正在尝试使用 vtkXMLPolyDataReader 而您应该使用 vtkPolyDataReader(这实际上取决于用于生成文件的编写器)。 vtkXMLPolyDataReader 是 .vtp 文件的标准阅读器。

最后，您将在循环内创建一个渲染器、一个渲染窗口和一个相机:这意味着每个对象一个窗口。不常见，是你想要的吗？

长话短说:您至少需要一个渲染器和一个窗口来显示一个或多个模型。您的模型分别由一个类型转换示:窗口是渲染器绘制(一个或多个) Actor 的地方。渲染器是一个渲染 channel :当然，您可以为每个 Actor 设置一个渲染 channel ，但除非您确定需要它，否则您不需要。

这是您的代码，按照我在您那里所做的修改:

int main(int argc, char *argv[])
{
    std::string directoryName = "D:\\3d models\\Dist\\" ;

    vtkSmartPointer<vtkOpenVRRenderer> renderer =
        vtkSmartPointer<vtkOpenVRRenderer>::New();
    vtkSmartPointer<vtkOpenVRRenderWindow> renderWindow =
            vtkSmartPointer<vtkOpenVRRenderWindow>::New();
    renderWindow->AddRenderer(renderer);
    vtkSmartPointer<vtkOpenVRRenderWindowInteractor> renderWindowInteractor =
            vtkSmartPointer<vtkOpenVRRenderWindowInteractor>::New();
    renderWindowInteractor->SetRenderWindow(renderWindow);
    vtkNew<vtkOpenVRCamera> cam;
    renderer->SetActiveCamera(cam);
    renderer->SetBackground(.2, .3, .4);

    vtkSmartPointer<vtkDirectory> directory = vtkSmartPointer<vtkDirectory>::New();
    int opened = directory->Open(directoryName.c_str());

    if(!opened)
    {
        std::cout << "No es posible abrir este directorio!" << std::endl;
        return EXIT_FAILURE;
    }

    int numberOfFiles = directory->GetNumberOfFiles();
    std::cout << "NUmero de archivos: " << numberOfFiles << std::endl;

    for (int i = 0; i < numberOfFiles; i++)
    {
        std::string fileString = directoryName;
        ////fileString += "/";
        fileString += directory->GetFile(i);

        std::string ext = vtksys::SystemTools::GetFilenameLastExtension(fileString);
        std::cout << fileString.c_str() << " extension: " << ext << std::endl;

        if (ext.find(".vtp") == std::string::npos) continue;

        std::string name = vtksys::SystemTools::GetFilenameWithoutLastExtension(fileString);    
        std::cout << "nombre: " << name << std::endl;

        const char*cstr = fileString.c_str();
        std::cout << cstr << endl;

        vtkSmartPointer<vtkXMLPolyDataReader> reader =
                vtkSmartPointer<vtkXMLPolyDataReader>::New();
        reader->SetFileName(cstr);
        reader->Update();
        reader->GetOutput();

        vtkSmartPointer<vtkTransform> transform =
                vtkSmartPointer<vtkTransform>::New();
        transform->Scale(.005, .005, .005);

        vtkSmartPointer<vtkTransformFilter> transformFilter =
                vtkSmartPointer<vtkTransformFilter>::New();
        transformFilter->SetInputConnection(reader->GetOutputPort());
        transformFilter->SetTransform(transform);

        // Visualizar
        vtkSmartPointer<vtkPolyDataMapper> mapper =
                vtkSmartPointer<vtkPolyDataMapper>::New();
        mapper->SetInputConnection(transformFilter->GetOutputPort());

        vtkSmartPointer<vtkActor> actor =
                vtkSmartPointer<vtkActor>::New();
        actor->SetPosition(1.1, .5, .1);
        actor->SetMapper(mapper);

        renderer->AddActor(actor);
    }

    renderWindow->Render();
    renderWindowInteractor->Start();

    return EXIT_SUCCESS;
}