Function LoadRenderModelMapping

Rendering/OpenXR/vtkOpenXRRenderWindow.cxx:51–131

---------------------------------------------------------------------------- OpenXR does not yet have a way to load and render controller models. This workaround maps known/tested interaction profiles to local assets.

  // models. This workaround maps known/tested interaction profiles
  // to local assets.
  void LoadRenderModelMapping()
  {
    std::string modelsFile = "openxr_controllermodels.json";

    // Look for where the function "GetVTKVersion." lives.
    auto vtklib = vtkGetLibraryPathForSymbol(GetVTKVersion);

    if (vtklib.empty())
    {
      vtkWarningWithObjectMacro(nullptr, << "Unable to locate runtime library location.");
      return;
    }

    // Search for the controller models json file in the parent of the
    // directory containing the library/executable.
    const std::string libPath = vtksys::SystemTools::GetFilenamePath(vtklib);
    const std::string rootSearchDir = vtksys::SystemTools::GetParentDirectory(libPath);
    vtkNew<vtkGlobFileNames> fileGlobber;
    fileGlobber->SetDirectory(rootSearchDir.c_str());
    fileGlobber->SetRecurse(true);
    fileGlobber->AddFileNames(modelsFile.c_str());
    if (!this->ModelsManifestDirectory.empty())
    {
      std::string fullpath =
        vtksys::SystemTools::JoinPath({ this->ModelsManifestDirectory, modelsFile });
      fileGlobber->AddFileNames(fullpath.c_str());
    }
    if (fileGlobber->GetNumberOfFileNames() <= 0)
    {
      vtkWarningWithObjectMacro(
        nullptr, << "Unable to locate model mapping file in: " << rootSearchDir);
      return;
    }

    const char* match = fileGlobber->GetNthFileName(0);
    const std::string modelFile(&match[0]);

    // Get the directory containing the controller models json file, since
    // we found it.
    std::string modelsDirectory = vtksys::SystemTools::GetFilenamePath(modelFile);

    // Open the profile->asset mapping file
    vtksys::ifstream file;
    file.open(modelFile.c_str());
    if (!file.is_open())
    {
      vtkWarningWithObjectMacro(nullptr, << "Unable to open model mapping file : " << modelFile);
      return;
    }

    Json::Value root;
    Json::CharReaderBuilder builder;
    std::string formattedErrors;
    if (!Json::parseFromStream(builder, file, &root, &formattedErrors))
    {
      // Report failures and their locations in the document
      vtkWarningWithObjectMacro(nullptr, << "Failed to parse file with errors :" << endl
                                         << formattedErrors);