从网格渲染RGB-D图像

为了从相机获得真实世界的深度，我做了以下工作：

    
      double z = render_win->GetZbufferDataAtPoint(x,y);
worldPicker->Pick(x, y, z, renderer);
worldPicker->GetPickPosition(coords);
double euclidean_distance = sqrt(pow((coords[0] - cam_pos[0]), 2) + pow(coords[1] - cam_pos[1], 2) + pow(coords[2] - cam_pos[2], 2));
</code>
  

如果你已经有应用程序设置和渲染，这里有几行，这必须在网格渲染至少一次之后

    
      // Screenshot
vtkSmartPointer windowToImageFilter =
vtkSmartPointer::New();
windowToImageFilter->SetInput(renderWindow);
windowToImageFilter->SetMagnification(3); //set the resolution of the output image (3     times the current resolution of vtk render window)
windowToImageFilter->SetInputBufferTypeToRGBA(); //also record the alpha (transparency)   channel
windowToImageFilter->Update();
vtkSmartPointer writer =
  vtkSmartPointer::New();
writer->SetFileName(“screenshot2.png”);
writer->SetInputConnection(windowToImageFilter->GetOutputPort());
writer->Write();
</code>
  

要检索RGB图像，您可以使用

vtkWindowToImageFilter

class，允许从vtkWindow读取数据。
对于深度图像，我尝试了一种解决方案，即使用修改网格上的颜色

vtkDepthSortPolyData

，再次，从窗口阅读。

见上面的例子：

    
  # define VTK_CREATE(type, nom) vtkSmartPointer<type> nom = vtkSmartPointer<type>::New()
int main ()
   {
      VTK_CREATE(vtkPLYReader, reader);
      reader->SetFileName (“mesh.ply”);
      reader->Update ();
  // create depth sort algo
  VTK_CREATE(vtkDepthSortPolyData, sort);
  sort->SetInput(reader->GetOutput ());
  // init stuff for rendering
  VTK_CREATE(vtkPolyDataMapper, mapper);
  VTK_CREATE(vtkActor, actor);
  VTK_CREATE(vtkRenderer, rend);
  VTK_CREATE(vtkRenderWindow, rw);
  VTK_CREATE(vtkRenderWindowInteractor, inte);
  VTK_CREATE(vtkCamera, cam);
  sort->SetDirectionToBackToFront (); // camera direction
  sort->SetCamera (cam); // set camera or runtime warning
  sort->SortScalarsOn ();
  sort->Update ();
  mapper->SetScalarVisibility(true);
  // limit max scalar (nb Color)
  mapper->SetScalarRange (0, sort->GetOutput ()->GetNumberOfCells ());
  mapper->SetInputConnection(sort->GetOutputPort ());
  mapper->Update ();
  actor->SetMapper(mapper);
  actor->RotateY (59); // transform with a rotation to see depth
  actor->GetProperty()->SetColor(1, 0, 0);
  sort->SetProp3D (actor); // set the actor to the algo
  rend->SetActiveCamera (cam);
  rw->AddRenderer(rend);
  rend->AddActor(actor);
  inte->SetRenderWindow (rw);
  inte->Initialize ();
  // read depth image from vtk Window
  VTK_CREATE (vtkWindowToImageFilter, screen);
  screen->SetInput (rw);
  screen->Update ();
  // start rendering for visualization
  rw->Render ();
  // save the depth img as a png
  VTK_CREATE(vtkPNGWriter, writer);
  writer->SetFileName ("output.png");
  writer->SetInputConnection (screen->GetOutputPort ());
  writer->Write ();
  inte->Start ();
  return 0;
}
</code>