Function displayFunc

tutorials/common/tutorial/tutorial.cpp:699–701

    TutorialApplication::instance->motionFunc(window,x,y);
  }
  void displayFunc() {
    TutorialApplication::instance->displayFunc();
  }
  void reshapeFunc(GLFWwindow* window, int width, int height) {
    TutorialApplication::instance->reshapeFunc(window,width,height);
  }