/*
 *		THX to nehe.gamedev.net for basecode
 */

#include <windows.h>		// Header File For Windows
#include <stdio.h>			// Header File For Standard Input/Output
#include <math.h>
#include <gl\gl.h>			// Header File For The OpenGL32 Library
#include <gl\glu.h>			// Header File For The GLu32 Library
#include <gl\glaux.h>		// Header File For The Glaux Library

#include "HPTime.h"

HDC			hDC=NULL;		// Private GDI Device Context
HGLRC		hRC=NULL;		// Permanent Rendering Context
HWND		hWnd=NULL;		// Holds Our Window Handle
HINSTANCE	hInstance;		// Holds The Instance Of The Application

bool	keys[256];			// Array Used For The Keyboard Routine
bool	active=TRUE;		// Window Active Flag Set To TRUE By Default
bool	fullscreen=TRUE;	// Fullscreen Flag Set To Fullscreen Mode By Default

GLfloat	xrot;				// X Rotation
GLfloat	yrot;				// Y Rotation
GLfloat xspeed=.0;				// X Rotation Speed
GLfloat yspeed=.12;				// Y Rotation Speed
GLfloat	z=-10.0f;			// Depth Into The Screen

GLfloat LightAmbient[]=		{ 0.5f, 0.5f, 0.5f, 1.0f };
GLfloat LightDiffuse[]=		{ 1.0f, 1.0f, 1.0f, 1.0f };
GLfloat LightPosition[]=	{ 0.0f, 0.0f, 4.0f, 1.0f };

long g_LVert = 0;

GLuint	g_DL_MStrip;
bool g_bDLMStripinit=false;

double g_dFrameTime=0;
double g_dFUpdate = 0;

#define PI 3.14159265358979

#define _T_ROWS 256

float g_pppfVMoebius[256][_T_ROWS][3];
float g_pppfVMoebiusNormal[256][_T_ROWS][3];
float g_ppfLColor[512][3];

#define _T_START -1
#define _T_END 1
#define _S_START 0
#define _S_END (2*PI)
#define _DEC .02

LRESULT	CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);	// Declaration For WndProc

GLvoid ReSizeGLScene(GLsizei width, GLsizei height)		// Resize And Initialize The GL Window
{
	if (height==0)										// Prevent A Divide By Zero By
	{
		height=1;										// Making Height Equal One
	}

	glViewport(0,0,width,height);						// Reset The Current Viewport

	glMatrixMode(GL_PROJECTION);						// Select The Projection Matrix
	glLoadIdentity();									// Reset The Projection Matrix

	// Calculate The Aspect Ratio Of The Window
	gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.1f,100.0f);

	glMatrixMode(GL_MODELVIEW);							// Select The Modelview Matrix
	glLoadIdentity();									// Reset The Modelview Matrix
}

int InitGL(GLvoid)										// All Setup For OpenGL Goes Here
{
	g_HPTime.markTick();

	glShadeModel(GL_SMOOTH);							// Enable Smooth Shading
	glClearColor(0.0f, 0.0f, 0.0f, 0.5f);				// Black Background
	glClearDepth(1.0f);									// Depth Buffer Setup
	glEnable(GL_DEPTH_TEST);							// Enables Depth Testing
	glDepthFunc(GL_LEQUAL);								// The Type Of Depth Testing To Do
	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);	// Really Nice Perspective Calculations

	glLightfv(GL_LIGHT1, GL_AMBIENT, LightAmbient);		// Setup The Ambient Light
	glLightfv(GL_LIGHT1, GL_DIFFUSE, LightDiffuse);		// Setup The Diffuse Light
	glLightfv(GL_LIGHT1, GL_POSITION,LightPosition);	// Position The Light
	glEnable(GL_LIGHT1);								// Enable Light One

	glEnable(GL_CULL_FACE);		// face culling
	glCullFace(GL_BACK);		// because of strange normals in this case

	// set up moebius strip coordinates
	double dsStep = double(_S_END - _S_START) / 254.,
		dtStep = double(_T_END - _T_START) / _T_ROWS,
		ds,dt;
	int is,it,i;
	float pfTemp[3];
	float fAbs;

	memset(g_ppfLColor,0,sizeof(float)*3*512);
	for(is = 0; is < 256; is ++){
		for(it = 0; it < _T_ROWS; it ++){
			ds = double(is) * dsStep + _S_START;
			dt = double(it) * dtStep + _T_START;

			// coordinates
			g_pppfVMoebius[is][it][0] = 3 * cos(ds) + dt * sin(ds/2.);
			g_pppfVMoebius[is][it][1] = 3 * sin(ds);
			g_pppfVMoebius[is][it][2] = dt * cos(ds/2.);

			// normals
			pfTemp[0] = 3*cos(ds/2) * cos(ds);
			pfTemp[1] = .5 * ( -dt + 3 * sin(ds/2.) + 3 * sin(3.*ds/2.) );
			pfTemp[2] = -3. * cos(ds) * sin(ds/2.);
			fAbs = 1.f/sqrt(pfTemp[0]*pfTemp[0] + pfTemp[1]*pfTemp[1] + pfTemp[2]*pfTemp[2]);
			for(i=0;i<3;i++)
				g_pppfVMoebiusNormal[is][it][i] = pfTemp[i] * fAbs;
		}
	}

	return TRUE;										// Initialization Went OK
}

int DrawGLScene(GLvoid)									// Here's Where We Do All The Drawing
{
	static int iShow = 0;
	static long lVertDP = 0;

	g_LVert=lVertDP;

	g_dFrameTime = g_HPTime.getElapsed_d();
	g_HPTime.markTick();
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);	// Clear The Screen And The Depth Buffer
	glLoadIdentity();									// Reset The View
	glTranslatef(0.0f,0.0f,z);

	glRotatef(xrot,1.0f,0.0f,0.0f);
	glRotatef(yrot,0.0f,1.0f,0.0f);

	// create new display lists ... known bugs : when having to release RC, DLs are deleted
	if(!g_bDLMStripinit){
		g_bDLMStripinit = true;

		g_DL_MStrip = glGenLists(2);

		glNewList(g_DL_MStrip,GL_COMPILE);

		int is,it,istep=1;
		for(is = 0; is < 255; is +=istep){
			glBegin(GL_TRIANGLE_STRIP);
			for(it = 0; it < _T_ROWS; it +=istep){
				glNormal3fv(g_pppfVMoebiusNormal[is][it]);
				glVertex3fv(g_pppfVMoebius[is][it]);
				g_LVert++;

				glNormal3fv(g_pppfVMoebiusNormal[(is+istep)%256][it]);
				glVertex3fv(g_pppfVMoebius[(is+istep)%256][it]);
				g_LVert++;
			}
			glEnd();
		}

		for(is = 255-istep; is>0; is -= istep){
			glBegin(GL_TRIANGLE_STRIP);
			for(it = _T_ROWS-1; it; it -= istep){
				glNormal3f(-g_pppfVMoebiusNormal[is][it][0],
					-g_pppfVMoebiusNormal[is][it][1],
					-g_pppfVMoebiusNormal[is][it][2]);
				glVertex3fv(g_pppfVMoebius[is][it]);
				g_LVert++;

				glNormal3f(-g_pppfVMoebiusNormal[(is+istep)%256][it][0],
					-g_pppfVMoebiusNormal[(is+istep)%256][it][1],
					-g_pppfVMoebiusNormal[(is+istep)%256][it][2]);
				glVertex3fv(g_pppfVMoebius[(is+istep)%256][it]);
				g_LVert++;
			}
			glEnd();
		}
		glEndList();

		glNewList(g_DL_MStrip+1,GL_COMPILE);
		// "seele"
		glBegin(GL_LINE_STRIP);
		for(is = 0; is < 255; is ++){
			glVertex3f(g_pppfVMoebius[is][_T_ROWS/2][0] + g_pppfVMoebiusNormal[is][_T_ROWS/2][0]*.01f,
				g_pppfVMoebius[is][_T_ROWS/2][1] + g_pppfVMoebiusNormal[is][_T_ROWS/2][1]*.01f,
				g_pppfVMoebius[is][_T_ROWS/2][2] + g_pppfVMoebiusNormal[is][_T_ROWS/2][2]*.01f);
			g_LVert++;
		}
		glEnd();
		glBegin(GL_LINE_STRIP);
		for(is = 0; is < 255; is ++){
			glVertex3f(g_pppfVMoebius[is][_T_ROWS/2][0] - g_pppfVMoebiusNormal[is][_T_ROWS/2][0]*.01f,
				g_pppfVMoebius[is][_T_ROWS/2][1] - g_pppfVMoebiusNormal[is][_T_ROWS/2][1]*.01f,
				g_pppfVMoebius[is][_T_ROWS/2][2] - g_pppfVMoebiusNormal[is][_T_ROWS/2][2]*.01f);
			g_LVert++;
		}
		glEnd();
		glEndList();

		lVertDP = g_LVert;
	}

	// draw strip
	if(!keys['2'] && !keys['3'] || keys['1']){
		glEnable(GL_LIGHTING);
		glCallList(g_DL_MStrip);
		glDisable(GL_LIGHTING);
	}

	// draw 'seele'
	glColor3f(0,0,0);
	if(!keys['1'] && !keys['3'] || keys['2']){
		if(keys['2'])
			glColor3f(1,1,1);
		glCallList(g_DL_MStrip+1);
	}

	if(g_dFUpdate+1 < g_HPTime.getTime_d()){
		g_dFUpdate = g_HPTime.getTime_d();

		char szCaption[80];
		sprintf(szCaption,"Möbius Band %.1lf fps %liMVert/s",1./g_dFrameTime,long(g_LVert*1./g_dFrameTime)/1000000);
		SetWindowText(hWnd,szCaption);
	}

	// draw normals
	int is;
	static double dLastIncrement = g_HPTime.getTime_d();
	if(g_HPTime.getTime_d() - dLastIncrement > 0.015){
		dLastIncrement = g_HPTime.getTime_d();
		iShow ++;
		if(iShow>512)
			iShow = 0;

		// calculate this fade effect of normals
		for(is = 0; is < 255; is ++){			
			g_ppfLColor[is][0] += _DEC * (is/255. - g_ppfLColor[is][0]);
			g_ppfLColor[is][1] += _DEC * (0 - g_ppfLColor[is][1]);
			g_ppfLColor[is][2] += _DEC * (1.f-is/255. - g_ppfLColor[is][2]);

			g_ppfLColor[is+256][0] += _DEC * (1.f-is/255. - g_ppfLColor[is+256][0]);
			g_ppfLColor[is+256][1] += _DEC * (0 - g_ppfLColor[is+256][1]);
			g_ppfLColor[is+256][2] += _DEC * (is/255. - g_ppfLColor[is+256][2]);
		}
	}

	if(!keys['1'] && !keys['2']||keys['3']){
	glBegin(GL_LINES);
	for(is = 0; is < 255; is ++){			
		if(iShow == is || iShow-256 == is){
			g_ppfLColor[iShow][0] = g_ppfLColor[iShow][1] = g_ppfLColor[iShow][2] = 1;
		}

		glColor3fv(g_ppfLColor[is]);

		glVertex3fv(g_pppfVMoebius[is][_T_ROWS/2]);
		glVertex3f(g_pppfVMoebius[is][_T_ROWS/2][0] + g_pppfVMoebiusNormal[is][_T_ROWS/2][0] ,//* (g_ppfLColor[is][1]+1),
			g_pppfVMoebius[is][_T_ROWS/2][1] + g_pppfVMoebiusNormal[is][_T_ROWS/2][1] ,//* (g_ppfLColor[is][1]+1),
			g_pppfVMoebius[is][_T_ROWS/2][2] + g_pppfVMoebiusNormal[is][_T_ROWS/2][2]) ;//* (g_ppfLColor[is][1]+1));

		g_LVert++;g_LVert++;

		glColor3fv(g_ppfLColor[is+256]);

		glVertex3fv(g_pppfVMoebius[is][_T_ROWS/2]);
		glVertex3f(g_pppfVMoebius[is][_T_ROWS/2][0] - g_pppfVMoebiusNormal[is][_T_ROWS/2][0] ,//* (g_ppfLColor[is+256][1]+1),
			g_pppfVMoebius[is][_T_ROWS/2][1] - g_pppfVMoebiusNormal[is][_T_ROWS/2][1] ,//* (g_ppfLColor[is+256][1]+1),
			g_pppfVMoebius[is][_T_ROWS/2][2] - g_pppfVMoebiusNormal[is][_T_ROWS/2][2] );//* (g_ppfLColor[is+256][1]+1));

		g_LVert++;g_LVert++;
	}
	glEnd();
	}

	// just for orientation, 3 lines in the directions of the coordinate system
	glBegin(GL_LINES);
	glColor3f(1,0,0);
	glVertex3f(0,0,0);
	glVertex3f(1,0,0);

	glColor3f(0,1,0);
	glVertex3f(0,0,0);
	glVertex3f(0,1,0);

	glColor3f(0,0,1);
	glVertex3f(0,0,0);
	glVertex3f(0,0,1);
	glEnd();

	xrot+=xspeed * g_dFrameTime*100.f;
	yrot+=yspeed * g_dFrameTime*100.f;
	return TRUE;										// Keep Going
}

GLvoid KillGLWindow(GLvoid)								// Properly Kill The Window
{
	if (fullscreen)										// Are We In Fullscreen Mode?
	{
		ChangeDisplaySettings(NULL,0);					// If So Switch Back To The Desktop
		ShowCursor(TRUE);								// Show Mouse Pointer
	}

	if (hRC)											// Do We Have A Rendering Context?
	{
		if (!wglMakeCurrent(NULL,NULL))					// Are We Able To Release The DC And RC Contexts?
		{
			MessageBox(NULL,"Release Of DC And RC Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		}

		if (!wglDeleteContext(hRC))						// Are We Able To Delete The RC?
		{
			MessageBox(NULL,"Release RC Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		}
		hRC=NULL;										// Set RC To NULL
	}

	if (hDC && !ReleaseDC(hWnd,hDC))					// Are We Able To Release The DC
	{
		MessageBox(NULL,"Release DC Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		hDC=NULL;										// Set DC To NULL
	}

	if (hWnd && !DestroyWindow(hWnd))					// Are We Able To Destroy The Window?
	{
		MessageBox(NULL,"Error releasing hWnd.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		hWnd=NULL;										// Set hWnd To NULL
	}

	if (!UnregisterClass("OpenGL",hInstance))			// Are We Able To Unregister Class
	{
		MessageBox(NULL,"Could Not Unregister Class.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		hInstance=NULL;									// Set hInstance To NULL
	}
}

/*	This Code Creates Our OpenGL Window.  Parameters Are:					*
 *	title			- Title To Appear At The Top Of The Window				*
 *	width			- Width Of The GL Window Or Fullscreen Mode				*
 *	height			- Height Of The GL Window Or Fullscreen Mode			*
 *	bits			- Number Of Bits To Use For Color (8/16/24/32)			*
 *	fullscreenflag	- Use Fullscreen Mode (TRUE) Or Windowed Mode (FALSE)	*/
 
BOOL CreateGLWindow(char* title, int width, int height, int bits, bool fullscreenflag)
{
	GLuint		PixelFormat;			// Holds The Results After Searching For A Match
	WNDCLASS	wc;						// Windows Class Structure
	DWORD		dwExStyle;				// Window Extended Style
	DWORD		dwStyle;				// Window Style
	RECT		WindowRect;				// Grabs Rectangle Upper Left / Lower Right Values
	WindowRect.left=(long)0;			// Set Left Value To 0
	WindowRect.right=(long)width;		// Set Right Value To Requested Width
	WindowRect.top=(long)0;				// Set Top Value To 0
	WindowRect.bottom=(long)height;		// Set Bottom Value To Requested Height

	fullscreen=fullscreenflag;			// Set The Global Fullscreen Flag

	hInstance			= GetModuleHandle(NULL);				// Grab An Instance For Our Window
	wc.style			= CS_HREDRAW | CS_VREDRAW | CS_OWNDC;	// Redraw On Size, And Own DC For Window.
	wc.lpfnWndProc		= (WNDPROC) WndProc;					// WndProc Handles Messages
	wc.cbClsExtra		= 0;									// No Extra Window Data
	wc.cbWndExtra		= 0;									// No Extra Window Data
	wc.hInstance		= hInstance;							// Set The Instance
	wc.hIcon			= LoadIcon(NULL, IDI_WINLOGO);			// Load The Default Icon
	wc.hCursor			= LoadCursor(NULL, IDC_ARROW);			// Load The Arrow Pointer
	wc.hbrBackground	= NULL;									// No Background Required For GL
	wc.lpszMenuName		= NULL;									// We Don't Want A Menu
	wc.lpszClassName	= "OpenGL";								// Set The Class Name

	if (!RegisterClass(&wc))									// Attempt To Register The Window Class
	{
		MessageBox(NULL,"Failed To Register The Window Class.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;											// Return FALSE
	}

	if (fullscreen)												// Are We Still In Fullscreen Mode?
	{
		dwExStyle=WS_EX_APPWINDOW;								// Window Extended Style
		dwStyle=WS_POPUP;										// Windows Style
		ShowCursor(FALSE);										// Hide Mouse Pointer
	}
	else
	{
		dwExStyle=WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;			// Window Extended Style
		dwStyle=WS_OVERLAPPEDWINDOW;							// Windows Style
	}

	AdjustWindowRectEx(&WindowRect, dwStyle, FALSE, dwExStyle);		// Adjust Window To True Requested Size

	// Create The Window
	if (!(hWnd=CreateWindowEx(	dwExStyle,							// Extended Style For The Window
								"OpenGL",							// Class Name
								title,								// Window Title
								dwStyle |							// Defined Window Style
								WS_CLIPSIBLINGS |					// Required Window Style
								WS_CLIPCHILDREN,					// Required Window Style
								0, 0,								// Window Position
								WindowRect.right-WindowRect.left,	// Calculate Window Width
								WindowRect.bottom-WindowRect.top,	// Calculate Window Height
								NULL,								// No Parent Window
								NULL,								// No Menu
								hInstance,							// Instance
								NULL)))								// Dont Pass Anything To WM_CREATE
	{
		KillGLWindow();								// Reset The Display
		MessageBox(NULL,"Window Creation Error.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE
	}

	static	PIXELFORMATDESCRIPTOR pfd=				// pfd Tells Windows How We Want Things To Be
	{
		sizeof(PIXELFORMATDESCRIPTOR),				// Size Of This Pixel Format Descriptor
		1,											// Version Number
		PFD_DRAW_TO_WINDOW |						// Format Must Support Window
		PFD_SUPPORT_OPENGL |						// Format Must Support OpenGL
		PFD_DOUBLEBUFFER,							// Must Support Double Buffering
		PFD_TYPE_RGBA,								// Request An RGBA Format
		bits,										// Select Our Color Depth
		0, 0, 0, 0, 0, 0,							// Color Bits Ignored
		0,											// No Alpha Buffer
		0,											// Shift Bit Ignored
		0,											// No Accumulation Buffer
		0, 0, 0, 0,									// Accumulation Bits Ignored
		16,											// 16Bit Z-Buffer (Depth Buffer)  
		0,											// No Stencil Buffer
		0,											// No Auxiliary Buffer
		PFD_MAIN_PLANE,								// Main Drawing Layer
		0,											// Reserved
		0, 0, 0										// Layer Masks Ignored
	};
	
	if (!(hDC=GetDC(hWnd)))							// Did We Get A Device Context?
	{
		KillGLWindow();								// Reset The Display
		MessageBox(NULL,"Can't Create A GL Device Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE
	}

	if (!(PixelFormat=ChoosePixelFormat(hDC,&pfd)))	// Did Windows Find A Matching Pixel Format?
	{
		KillGLWindow();								// Reset The Display
		MessageBox(NULL,"Can't Find A Suitable PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE
	}

	if(!SetPixelFormat(hDC,PixelFormat,&pfd))		// Are We Able To Set The Pixel Format?
	{
		KillGLWindow();								// Reset The Display
		MessageBox(NULL,"Can't Set The PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE
	}

	if (!(hRC=wglCreateContext(hDC)))				// Are We Able To Get A Rendering Context?
	{
		KillGLWindow();								// Reset The Display
		MessageBox(NULL,"Can't Create A GL RC.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE
	}

	if(!wglMakeCurrent(hDC,hRC))					// Try To Activate The Rendering Context
	{
		KillGLWindow();								// Reset The Display
		MessageBox(NULL,"Can't Activate The GL RC.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE
	}

	ShowWindow(hWnd,SW_SHOW);						// Show The Window
	SetForegroundWindow(hWnd);						// Slightly Higher Priority
	SetFocus(hWnd);									// Sets Keyboard Focus To The Window
	ReSizeGLScene(width, height);					// Set Up Our Perspective GL Screen

	if (!InitGL())									// Initialize Our Newly Created GL Window
	{
		KillGLWindow();								// Reset The Display
		MessageBox(NULL,"Init Failed.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE
	}

	return TRUE;									// Success
}

LRESULT CALLBACK WndProc(	HWND	hWnd,			// Handle For This Window
							UINT	uMsg,			// Message For This Window
							WPARAM	wParam,			// Additional Message Information
							LPARAM	lParam)			// Additional Message Information
{
	switch (uMsg)									// Check For Windows Messages
	{
		case WM_ACTIVATE:							// Watch For Window Activate Message
		{
			if (!HIWORD(wParam))					// Check Minimization State
			{
				active=TRUE;						// Program Is Active
			}
			else
			{
				active=FALSE;						// Program Is No Longer Active
			}

			return 0;								// Return To The Message Loop
		}

		case WM_SYSCOMMAND:							// Intercept System Commands
		{
			switch (wParam)							// Check System Calls
			{
				case SC_SCREENSAVE:					// Screensaver Trying To Start?
				case SC_MONITORPOWER:				// Monitor Trying To Enter Powersave?
				return 0;							// Prevent From Happening
			}
			break;									// Exit
		}

		case WM_CLOSE:								// Did We Receive A Close Message?
		{
			PostQuitMessage(0);						// Send A Quit Message
			return 0;								// Jump Back
		}

		case WM_KEYDOWN:							// Is A Key Being Held Down?
		{
			keys[wParam] = TRUE;					// If So, Mark It As TRUE
			return 0;								// Jump Back
		}

		case WM_KEYUP:								// Has A Key Been Released?
		{
			keys[wParam] = FALSE;					// If So, Mark It As FALSE
			return 0;								// Jump Back
		}

		case WM_SIZE:								// Resize The OpenGL Window
		{
			ReSizeGLScene(LOWORD(lParam),HIWORD(lParam));  // LoWord=Width, HiWord=Height
			return 0;								// Jump Back
		}
	}

	// Pass All Unhandled Messages To DefWindowProc
	return DefWindowProc(hWnd,uMsg,wParam,lParam);
}

int WINAPI WinMain(	HINSTANCE	hInstance,			// Instance
					HINSTANCE	hPrevInstance,		// Previous Instance
					LPSTR		lpCmdLine,			// Command Line Parameters
					int			nCmdShow)			// Window Show State
{
	MSG		msg;									// Windows Message Structure
	BOOL	done=FALSE;								// Bool Variable To Exit Loop

	// Ask The User Which Screen Mode They Prefer
	//if (MessageBox(NULL,"Would You Like To Run In Fullscreen Mode?", "Start FullScreen?",MB_YESNO|MB_ICONQUESTION)==IDNO)
	fullscreen = FALSE;

	// Create Our OpenGL Window
	if (!CreateGLWindow("Möbius Band",800,600,32,fullscreen))
	{
		return 0;									// Quit If Window Was Not Created
	}

	while(!done)									// Loop That Runs While done=FALSE
	{
		if (PeekMessage(&msg,NULL,0,0,PM_REMOVE))	// Is There A Message Waiting?
		{
			if (msg.message==WM_QUIT)				// Have We Received A Quit Message?
			{
				done=TRUE;							// If So done=TRUE
			}
			else									// If Not, Deal With Window Messages
			{
				TranslateMessage(&msg);				// Translate The Message
				DispatchMessage(&msg);				// Dispatch The Message
			}
		}
		else										// If There Are No Messages
		{
			// Draw The Scene.  Watch For ESC Key And Quit Messages From DrawGLScene()
			if ((active && !DrawGLScene()) || keys[VK_ESCAPE])	// Active?  Was There A Quit Received?
			{
				done=TRUE;							// ESC or DrawGLScene Signalled A Quit
			}
			else									// Not Time To Quit, Update Screen
			{
				SwapBuffers(hDC);					// Swap Buffers (Double Buffering)
				if (keys[VK_PRIOR]){
					z-=0.02f;
				}
				if (keys[VK_NEXT]){
					z+=0.02f;
				}
				if (keys[VK_UP]){
					xspeed-=0.001f;
				}
				if (keys[VK_DOWN]){
					xspeed+=0.001f;
				}
				if (keys[VK_RIGHT]){
					yspeed+=0.001f;
				}
				if (keys[VK_LEFT]){
					yspeed-=0.001f;
				}
				if (keys[' ']){
					xspeed = yspeed = 0;
				}
			}
		}
	}

	// Shutdown
	KillGLWindow();									// Kill The Window
	return (msg.wParam);							// Exit The Program
}