此函数为glfw的封装函数
int CRenderEngine::RunMessageLoop()
{
	//初始化，设置OpenGL版本，以及核心模式
	glfwInit();
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

#ifdef __APPLE__
	// uncomment this statement to fix compilation on OS X
	glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endif

	//创建窗口
	GLFWwindow* pWindow = glfwCreateWindow(m_nWidth, m_nHeight, m_strTitle.c_str(), NULL, NULL);
	if (nullptr == pWindow)
	{
		std::cout << "Failed to create GLFW window" << std::endl;
		glfwTerminate();
		return -1;
	}
	glfwMakeContextCurrent(pWindow);

	//设置消息处理函数
	glfwSetKeyCallback(pWindow, key_callback);
	glfwSetMouseButtonCallback(pWindow, mouse_button_callback);
	glfwSetCursorPosCallback(pWindow, cursor_position_callback);
	glfwSetScrollCallback(pWindow, scroll_callback);
	glfwSetFramebufferSizeCallback(pWindow, framebuffer_size_callback);

	// glad: 载入所有OpenGL函数指针
	// ---------------------------------------
	if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
	{
		std::cout << "Failed to initialize GLAD" << std::endl;
		return -1;
	}

	CSceneManager *pSceneManager = GetRenderEngine()->GetSceneManager();
	pSceneManager->SetActiveScene(pSceneManager->GetActiveScene());

	//多边形绘制模式设定.
	//glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);

	float fFPS = 0;
	int nTotalFrame = 0;
	clock_t clockPreviorFrameTime;
	clock_t clockCurrentFrameTime;
	clock_t clockBeginFrameTime = clock();

	while (!glfwWindowShouldClose(pWindow))
	{	
		//清屏
		glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
		glClear(GL_COLOR_BUFFER_BIT);

		RenderScene(pSceneManager->GetActiveScene());
		//计算FPS
		nTotalFrame++;
		clockCurrentFrameTime = clock();
		float fTotalTime = (clockCurrentFrameTime - clockBeginFrameTime) / 1000;
		fFPS = nTotalFrame / fTotalTime;

		glfwSwapBuffers(pWindow);
		glfwPollEvents();
	}

	glfwTerminate();
	return 0;
}