VTK版本的HelloWorld，使用vtkNew创建对象

本篇博客介绍的是VTK版本的HelloWorld，没什么技术含量，目的是记录创建一个VTK项目的重复性操作，以及基本的VTK可视化渲染管线的基本知识。
VTK的可视化渲染一般都经历如下图所示的几个步骤：

CMakeLists.txt

cmake_minimum_required(VERSION 3.5)

project(CylinderExample LANGUAGES CXX)

set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
find_package(VTK REQUIRED)
if (NOT VTK_FOUND)
  message("Skipping CylinderExample: ${VTK_NOT_FOUND_MESSAGE}")
  return ()
endif()
message (STATUS "VTK_VERSION: ${VTK_VERSION}")
include(${VTK_USE_FILE})
add_executable(CylinderExample main.cpp)
target_link_libraries(CylinderExample PRIVATE ${VTK_LIBRARIES})

main.cpp

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#include 

int main(int, char *[]) {
    vtkNew<vtkNamedColors> colors;
    // Set the background color.
    std::array<unsigned char, 4> bkg{26, 51, 102, 255};
    colors->SetColor("BkgColor", bkg.data());
    // This creates a polygonal cylinder model with eight circumferential facets
    // (i.e, in practice an octagonal prism).
    vtkNew<vtkCylinderSource> cylinder;
    cylinder->SetResolution(8);
    // The mapper is responsible for pushing the geometry into the graphics
    // library. It may also do color mapping, if scalars or other attributes are
    // defined.
    vtkNew<vtkPolyDataMapper> cylinderMapper;
    cylinderMapper->SetInputConnection(cylinder->GetOutputPort());
    // The actor is a grouping mechanism: besides the geometry (mapper), it
    // also has a property, transformation matrix, and/or texture map.
    // Here we set its color and rotate it around the X and Y axes.
    vtkNew<vtkActor> cylinderActor;
    cylinderActor->SetMapper(cylinderMapper);
    cylinderActor->GetProperty()->SetColor(colors->GetColor4d("Tomato").GetData());
    cylinderActor->RotateX(30.0);
    cylinderActor->RotateY(-45.0);
    // The renderer generates the image
    // which is then displayed on the render window.
    // It can be thought of as a scene to which the actor is added
    vtkNew<vtkRenderer> renderer;
    renderer->AddActor(cylinderActor);
    renderer->SetBackground(colors->GetColor3d("BkgColor").GetData());
    // Zoom in a little by accessing the camera and invoking its "Zoom" method.
    renderer->ResetCamera();
    renderer->GetActiveCamera()->Zoom(1.5);
    // The render window is the actual GUI window
    // that appears on the computer screen
    vtkNew<vtkRenderWindow> renderWindow;
    renderWindow->SetSize(300, 300);
    renderWindow->AddRenderer(renderer);
    renderWindow->SetWindowName("Cylinder");
    // The render window interactor captures mouse events
    // and will perform appropriate camera or actor manipulation
    // depending on the nature of the events.
    vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
    renderWindowInteractor->SetRenderWindow(renderWindow);
    // This starts the event loop and as a side effect causes an initial render.
    renderWindow->Render();
    renderWindowInteractor->Start();
    return EXIT_SUCCESS;
}