请教关于OpenGL聚光灯的问题

class CBox

{

private:

	int		mWindowWidth;

	int		mWindowHeight;

	float	mAngle;

	float	s;

	float	c;

public:

	CBox();

	~CBox();



	bool init();

	bool ShutDown();



	void SetProjection(int width, int height);

	void Prepare(float fAngle);

	void Render();

	void Light();

};



float light[] = {1.0, 0.0, 0.0, 1.0};//灯光颜色

float position[] = {0.0, 1.0, 0.0, 1.0};//灯光位置，为点光源

float direction[] = {-1.0, -1.0, 0.0};//灯光方向



void CBox::Light()//设置灯光

{

	glEnable(GL_LIGHTING);

	glLightfv(GL_LIGHT0, GL_AMBIENT, light);

	glLightfv(GL_LIGHT0, GL_DIFFUSE, light);

	glLightfv(GL_LIGHT0, GL_SPECULAR, light);

	glLightfv(GL_LIGHT0, GL_POSITION, position);



	glLightfv(GL_LIGHT0, GL_SPOT_DIRECTION, direction);

	glLightf(GL_LIGHT0, GL_SPOT_EXPONENT, 0.0);

	glLightf(GL_LIGHT0, GL_SPOT_CUTOFF, 30.0);



	glEnable(GL_LIGHT0);

}



float material1[] = {0.0, 0.0, 0.0, 1.0};//材质1不反射任何颜色

float material2[] = {1.0, 1.0, 1.0, 1.0};//材质2反射所以颜色



float x = 1.0;



void CBox::Render()

{

	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

	glLoadIdentity();

	gluLookAt(2.0, -2.0, 0.0, -1.0, 1.0, 0.0, 0.0, 0.0, 1.0);



	Light();



	glMaterialfv(GL_FRONT,GL_AMBIENT, material1);

	glMaterialfv(GL_FRONT, GL_DIFFUSE, material1);

	glMaterialfv(GL_FRONT, GL_SPECULAR, material2);//使平面只有反射光



	glBegin(GL_QUADS);//在X轴-1出垂直X轴画一个平面

		glNormal3f(1.0, 0.0, 0.0);

		glVertex3f(-x, x, x);

		glVertex3f(-x, x, -x);

		glVertex3f(-x, -x, -x);

		glVertex3f(-x, -x, x);

	glEnd();

}





int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,

				   LPSTR lpCmdLine, int nShowCmd)

{

	WNDCLASSEX	windowClass;

	HWND		hwnd;

	MSG			msg;

	DWORD		dwExStyle;

	DWORD		dwStyle;

	RECT		windowRect;







	windowRect.left		= (long)0;

	windowRect.right	= (long)windowWidth;

	windowRect.top		= (long)0;

	windowRect.bottom	= (long)windowHeight;



	memset(&windowClass, 0, sizeof(WNDCLASSEX));



	windowClass.cbSize			= sizeof(WNDCLASSEX);

	windowClass.style			= CS_HREDRAW | CS_VREDRAW;

	windowClass.lpfnWndProc		= MainWindowProc;

	windowClass.cbClsExtra		= 0;

	windowClass.cbWndExtra		= 0;

	windowClass.hInstance		= hInstance;

	windowClass.hIcon			= LoadIcon(NULL, IDI_APPLICATION);

	windowClass.hCursor			= LoadCursor(NULL, IDC_ARROW);

	windowClass.hbrBackground	= NULL;

	windowClass.lpszClassName	= "OpenGL";

	windowClass.hIconSm			= LoadIcon(NULL, IDI_WINLOGO);



	if( !RegisterClassEx(&windowClass))

		return 0;



	dwExStyle	= WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;

	dwStyle		= WS_OVERLAPPEDWINDOW;



	AdjustWindowRectEx(&windowRect, dwStyle, FALSE, dwExStyle);



	hwnd = CreateWindowEx(NULL, "OpenGL",

		"myOpenGL", dwStyle | WS_CLIPCHILDREN | WS_CLIPSIBLINGS,

		0, 0,

		windowRect.right - windowRect.left,

		windowRect.bottom - windowRect.top,

		NULL, NULL, hInstance, NULL);



	hDC = GetDC(hwnd);

	mBox = new CBox;



	if( !hwnd )

		return 0;



	ShowWindow(hwnd, SW_SHOW);

	UpdateWindow(hwnd);



	mBox->init();



	while( exiting )

	{

		mBox->Prepare(0.0f);

		mBox->Render();

		SwapBuffers(hDC);



		while( PeekMessage(&msg, NULL, 0, 0, PM_NOREMOVE) )

		{

			if( !GetMessage(&msg, NULL, 0, 0) )

			{

		//		exiting = true;

				break;

			}



			TranslateMessage(&msg);

			DispatchMessage(&msg);

		}

	}



	return (int)msg.wParam;

}