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Haku

two different opengl sources

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I have the original nehe tutorial of rotating polygons and a modified version. The modified version is very efficient as it contains half as much code as the original, i dont think it has any handles either. I also noticed that in nehe's original tutorial uses the header file glu.h whereas the modified one uses glut.h, what are the differences between the two? NAd my overal question is which will better to use, the modified nehe tutorial or the original, here are the two sources... Nehe's original:
[source=cpp]
/*
 *		This Code Was Created By Jeff Molofee 2000
 *		A HUGE Thanks To Fredric Echols For Cleaning Up
 *		And Optimizing The Base Code, Making It More Flexible!
 *		If You've Found This Code Useful, Please Let Me Know.
 *		Visit My Site At nehe.gamedev.net
 */

#include <windows.h>		// Header File For Windows
#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

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	rtri;				// Angle For The Triangle ( NEW )
GLfloat	rquad;				// Angle For The Quad ( NEW )

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
{
	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
	return TRUE;										// Initialization Went OK
}

int DrawGLScene(GLvoid)									// Here's Where We Do All The Drawing
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);	// Clear Screen And Depth Buffer
	glLoadIdentity();									// Reset The Current Modelview Matrix
	glTranslatef(-1.5f,0.0f,-6.0f);						// Move Left 1.5 Units And Into The Screen 6.0
	glRotatef(rtri,0.0f,1.0f,0.0f);						// Rotate The Triangle On The Y axis ( NEW )
	glBegin(GL_TRIANGLES);								// Start Drawing A Triangle
		glColor3f(1.0f,0.0f,0.0f);						// Set Top Point Of Triangle To Red
		glVertex3f( 0.0f, 1.0f, 0.0f);					// First Point Of The Triangle
		glColor3f(0.0f,1.0f,0.0f);						// Set Left Point Of Triangle To Green
		glVertex3f(-1.0f,-1.0f, 0.0f);					// Second Point Of The Triangle
		glColor3f(0.0f,0.0f,1.0f);						// Set Right Point Of Triangle To Blue
		glVertex3f( 1.0f,-1.0f, 0.0f);					// Third Point Of The Triangle
	glEnd();											// Done Drawing The Triangle
	glLoadIdentity();									// Reset The Current Modelview Matrix
	glTranslatef(1.5f,0.0f,-6.0f);						// Move Right 1.5 Units And Into The Screen 6.0
	glRotatef(rquad,1.0f,0.0f,0.0f);					// Rotate The Quad On The X axis ( NEW )
	glColor3f(0.5f,0.5f,1.0f);							// Set The Color To Blue One Time Only
	glBegin(GL_QUADS);									// Draw A Quad
		glVertex3f(-1.0f, 1.0f, 0.0f);					// Top Left
		glVertex3f( 1.0f, 1.0f, 0.0f);					// Top Right
		glVertex3f( 1.0f,-1.0f, 0.0f);					// Bottom Right
		glVertex3f(-1.0f,-1.0f, 0.0f);					// Bottom Left
	glEnd();											// Done Drawing The Quad
	rtri+=0.2f;											// Increase The Rotation Variable For The Triangle ( NEW )
	rquad-=0.15f;										// Decrease The Rotation Variable For The Quad ( NEW )
	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 Rendering Context 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 Device Context 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,"Could Not Release 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)												// Attempt Fullscreen Mode?
	{
		DEVMODE dmScreenSettings;								// Device Mode
		memset(&dmScreenSettings,0,sizeof(dmScreenSettings));	// Makes Sure Memory's Cleared
		dmScreenSettings.dmSize=sizeof(dmScreenSettings);		// Size Of The Devmode Structure
		dmScreenSettings.dmPelsWidth	= width;				// Selected Screen Width
		dmScreenSettings.dmPelsHeight	= height;				// Selected Screen Height
		dmScreenSettings.dmBitsPerPel	= bits;					// Selected Bits Per Pixel
		dmScreenSettings.dmFields=DM_BITSPERPEL|DM_PELSWIDTH|DM_PELSHEIGHT;

		// Try To Set Selected Mode And Get Results.  NOTE: CDS_FULLSCREEN Gets Rid Of Start Bar.
		if (ChangeDisplaySettings(&dmScreenSettings,CDS_FULLSCREEN)!=DISP_CHANGE_SUCCESSFUL)
		{
			// If The Mode Fails, Offer Two Options.  Quit Or Use Windowed Mode.
			if (MessageBox(NULL,"The Requested Fullscreen Mode Is Not Supported By\nYour Video Card. Use Windowed Mode Instead?","NeHe GL",MB_YESNO|MB_ICONEXCLAMATION)==IDYES)
			{
				fullscreen=FALSE;		// Windowed Mode Selected.  Fullscreen = FALSE
			}
			else
			{
				// Pop Up A Message Box Letting User Know The Program Is Closing.
				MessageBox(NULL,"Program Will Now Close.","ERROR",MB_OK|MB_ICONSTOP);
				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 Rendering Context.","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 Rendering Context.","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,"Initialization 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;							// Windowed Mode
	}

	// Create Our OpenGL Window
	if (!CreateGLWindow("NeHe's Rotation Tutorial",640,480,16,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_F1])						// Is F1 Being Pressed?
			{
				keys[VK_F1]=FALSE;					// If So Make Key FALSE
				KillGLWindow();						// Kill Our Current Window
				fullscreen=!fullscreen;				// Toggle Fullscreen / Windowed Mode
				// Recreate Our OpenGL Window
				if (!CreateGLWindow("NeHe's Rotation Tutorial",640,480,16,fullscreen))
				{
					return 0;						// Quit If Window Was Not Created
				}
			}
		}
	}

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

modified:
[source=cpp]
//
// This code was created by Jeff Molofee '99 (ported to Linux/GLUT by Richard Campbell '99)
//
// If you've found this code useful, please let me know.
//
// Visit me at www.demonews.com/hosted/nehe 
// (email Richard Campbell at ulmont@bellsouth.net)
//
#include <GL/glut.h>    // Header File For The GLUT Library 
#include <GL/gl.h> // Header File For The OpenGL32 Library
#include <GL/glu.h> // Header File For The GLu32 Library
#include <unistd.h>     // Header File For sleeping.

/* ASCII code for the escape key. */
#define ESCAPE 27

/* The number of our GLUT window */
int window; 

/* rotation angle for the triangle. */
float rtri = 0.0f;

/* rotation angle for the quadrilateral. */
float rquad = 0.0f;
float pos=0; // Triangle position
/* A general OpenGL initialization function.  Sets all of the initial parameters. */
void InitGL(int Width, int Height)         // We call this right after our OpenGL window is created.
{
  glClearColor(1.0f, 0.0f, 0.0f, 0.0f);  // This Will Clear The Background Color To Black
  glClearDepth(1.0);    // Enables Clearing Of The Depth Buffer
  glDepthFunc(GL_LESS);    // The Type Of Depth Test To Do
  glEnable(GL_DEPTH_TEST);   // Enables Depth Testing
  glShadeModel(GL_SMOOTH);   // Enables Smooth Color Shading

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

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

  glMatrixMode(GL_MODELVIEW);
}

/* The function called when our window is resized (which shouldn't happen, because we're fullscreen) */
void ReSizeGLScene(int Width, int Height)
{
  if (Height==0)    // Prevent A Divide By Zero If The Window Is Too Small
    Height=1;

  glViewport(0, 0, Width, Height);  // Reset The Current Viewport And Perspective Transformation

  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();

  gluPerspective(45.0f,(GLfloat)Width/(GLfloat)Height,0.1f,100.0f);
  glMatrixMode(GL_MODELVIEW);
}

/* The main drawing function. */
void DrawGLScene()
{

  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);  // Clear The Screen And The Depth Buffer
  glLoadIdentity();    // Reset The View

  glTranslatef(-1.5f + pos,0.0f,-1.0f);  // Move Left 1.5 Units And Into The Screen 6.0
 
  glRotatef(rtri,0.0f,1.0f,0.0f);  // Rotate The Triangle On The Y axis 
  // draw a triangle (in smooth coloring mode)
  glBegin(GL_POLYGON);    // start drawing a polygon
  glColor3f(1.0f,0.0f,0.0f);   // Set The Color To Red
  glVertex3f( 0.0f, 1.0f, 0.0f);  // Top
  glColor3f(0.0f,1.0f,0.0f);   // Set The Color To Green
  glVertex3f( 1.0f,-1.0f, 0.0f);  // Bottom Right
  glColor3f(0.0f,0.0f,1.0f);   // Set The Color To Blue
  glVertex3f(-1.0f,-1.0f, 0.0f);  // Bottom Left 
  glEnd();     // we're done with the polygon (smooth color interpolation)

  glLoadIdentity();    // make sure we're no longer rotated.
  glTranslatef(1.5f,0.0f,-6.0f);  // Move Right 3 Units, and back into the screen 6.0
 
  glRotatef(rquad,1.0f,0.0f,0.0f);  // Rotate The Quad On The X axis 
  // draw a square (quadrilateral)
  glColor3f(0.5f,0.5f,1.0f);   // set color to a blue shade.
  glBegin(GL_QUADS);    // start drawing a polygon (4 sided)
  glVertex3f(-1.0f, 1.0f, 0.0f);  // Top Left
  glVertex3f( 1.0f, 1.0f, 0.0f);  // Top Right
  glVertex3f( 1.0f,-1.0f, 0.0f);  // Bottom Right
  glVertex3f(-1.0f,-1.0f, 0.0f);  // Bottom Left 
  glEnd();     // done with the polygon

  rtri+=1.0f;     // Increase The Rotation Variable For The Triangle
  rquad-=1.0f;     // Decrease The Rotation Variable For The Quad 

  // swap the buffers to display, since double buffering is used.
  glutSwapBuffers();
  
}
void idle()
{
 
 DrawGLScene();
}
/* The function called whenever a key is pressed. */
void keyPressed(unsigned char key, int x, int y) 
{
    /* sleep to avoid thrashing this procedure */
    //usleep(10);

    /* If escape is pressed, kill everything. */
 //pos = (GLfloat)x/(GLfloat)y;
 if (key == '3')
 {
  pos += 0.1;
 }
 if(key == '2')
  pos -= 0.1;
    if (key == ESCAPE) 
    { 
 /* shut down our window */
 glutDestroyWindow(window); 
 
 /* exit the program...normal termination. */
 exit(0);                   
    }
}

int main(int argc, char **argv) 
{  
  /* Initialize GLUT state - glut will take any command line arguments that pertain to it or 
     X Windows - look at its documentation at http://reality.sgi.com/mjk/spec3/spec3.html */  
  glutInit(&argc, argv);  

  /* Select type of Display mode:   
     Double buffer 
     RGBA color
     Alpha components supported 
     Depth buffer */  
  glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_ALPHA | GLUT_DEPTH);  

  /* get a 640 x 480 window */
  glutInitWindowSize(640, 480);  

  /* the window starts at the upper left corner of the screen */
  glutInitWindowPosition(0, 0);  

  /* Open a window */  
  window = glutCreateWindow("Jeff Molofee's GL Code Tutorial ... NeHe '99");  

  /* Register the function to do all our OpenGL drawing. */
  glutDisplayFunc(&DrawGLScene);  

  /* Go fullscreen.  This is as soon as possible. */
  glutFullScreen();

  /* Even if there are no events, redraw our gl scene. */
  glutIdleFunc(&idle);

  /* Register the function called when our window is resized. */
  glutReshapeFunc(&ReSizeGLScene);

  /* Register the function called when the keyboard is pressed. */
  glutKeyboardFunc(&keyPressed);

  /* Initialize our window. */
  InitGL(640, 480);
  
  /* Start Event Processing Engine */  
  glutMainLoop();  

  return 1;
}

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The first uses Windows and the wgl functions to interface with OpenGL, the second is a port to Linux and uses the GLUT library for its Window system. Neither is necessarily more efficient, they are just meant for a different platform.

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Quote:
Original post by Haku
I also noticed that in nehe's original tutorial uses the header file glu.h whereas the modified one uses glut.h, what are the differences between the two?


GLU is part of OpenGL, GLUT is not. And both do very different things.

GLU is a set of routines that provide higher-level OpenGL functionality, such as asking for a perspective projection instead of definining the projection matrix by hand.

GLUT is a portable windowing wrapper. It takes care of creating the windows, handling events (like window resize, mouse clicks...). It essentially provides your application's main loop (glutMainLoop!). It has the advantage of letting you easily write portable code (without any Win32-specific stuff), but is not as flexible as targeting the platform's API.

In fact, the glut.h header does include glu.h so...

Quote:
NAd my overal question is which will better to use, the modified nehe tutorial or the original, here are the two sources...


Neither is. It all depends on your preferences. There are multiple GLUT implementations, there are other wrapper libraries, such as SDL, which offer even more functionality.

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You could also use GLFW as an alternative to GLUT. Here's a sample of a basic demo:

#include <stdlib.h>
#define GLFW_DLL
#include <GL/glfw.h>

#pragma comment ( lib, "Opengl32.lib" )
#pragma comment ( lib, "glu32.lib" )
#pragma comment ( lib, "GLFW.lib" )

int main()
{
if ( glfwInit() != GL_TRUE )
exit( 0 );

if ( glfwOpenWindow( 640, 480, 5, 6, 5, 0, 0, 0, GLFW_WINDOW) != GL_TRUE )
{
glfwTerminate();
exit( 0 );
}

glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glFrustum(.5, -.5, -.5 * ((float)480.0f) / 640.0f, .5 * ((float)480.0f) / 640.0f, 1, 50);
glMatrixMode(GL_MODELVIEW);
while( 1 )
{
if ( glfwGetKey(GLFW_KEY_ESC) == GLFW_PRESS )
break;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity( );
/****************************************/
glTranslatef( 0, 0, -5 );
glColor3f(0.5f,0.5f,1.0f);
glBegin(GL_QUADS);
glVertex3f(-1.0f, 1.0f, 0.0f);
glVertex3f( 1.0f, 1.0f, 0.0f);
glVertex3f( 1.0f,-1.0f, 0.0f);
glVertex3f(-1.0f,-1.0f, 0.0f);
glEnd();
/****************************************/
glfwSwapBuffers();
}
glfwTerminate();
exit( 0 );
}






You will have to build the GLFW lbirary yourself though, which can be a little confusing at first, but after that, working with GLFW is quite easy! Just a suggestion. You should also take a look, as Fruny has said, into using SDL with OpenGL, it's a lot easier than GLFW.

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thanks gys for ur replys, is it possible to combine glut and glu so i can be lazy and write less code as i wont have to declare the handles and windows stuff?

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If you really must compare header files, sompare glut.h to windows.h

While all the handle stuff in the windowing code can be confusing at first, since you're primarily working with OpenGL, it's not too hard to drop in some code that works and never look at it again.

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