Pointer to WndProc in a class

//// Header//class Window{public:   //...protected:   static LRESULT CALLBACK StaticWndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);   LRESULT WndProc(UINT uMsg, WPARAM wParam, LPARAM lParam);protected:   HWND   m_hWnd;};//// Source//// When you register the window class, pass CWindow::StaticWndProc as the window message procedure pointer// When you create the window, pass "this" as the extra parameterm_hWnd = CreateWindowEx(0,"Classname","Title",WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,320,200,NULL,NULL,hInstance,this);// Now for the real code:LRESULT CALLBACK CWindow::StaticWndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam){CWindow* pParent;   // Get pointer to window   if(uMsg == WM_CREATE)   {      pParent = (CWindow*)((LPCREATESTRUCT)lParam)->lpCreateParams;      SetWindowLongPtr(hWnd,GWL_USERDATA,(LONG_PTR)pParent);   }   else   {      pParent = (CWindow*)GetWindowLongPtr(hWnd,GWL_USERDATA);      if(!pParent) return DefWindowProc(hWnd,uMsg,wParam,lParam);   }   pParent->m_hWnd = hWnd;   return pParent->WndProc(uMsg,wParam,lParam);}LRESULT CWindow::WndProc(UINT uMsg, WPARAM wParam, LPARAM lParam){   switch(uMsg)   {      // Normal code here   }   // Call default window proc if we haven't handled the message   return DefWindowProc(m_hWnd,uMsg,wParam,lParam);}

// CWindow.h:#ifndef INC_CWindow_H#define INC_CWindow_H#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 Libraryclass CWindow {  public:    CWindow();    BOOL CWindow::CreateGLWindow(char* title, int width, int height, int bits, bool fullscreenflag);    GLvoid KillGLWindow(GLvoid);    static LRESULT	CALLBACK StaticWndProc(HWND, UINT, WPARAM, LPARAM);	// Declaration For WndProc    LRESULT WndProc( UINT, WPARAM, LPARAM);    int InitGL(GLvoid);        HDC gethDC() { return hDC; };  private:    HDC			hDC;		// Private GDI Device Context    HGLRC		hRC;		// Permanent Rendering Context    HWND		hWnd;		// Holds Our Window Handle    HINSTANCE	hInstance;		// Holds The Instance Of The Application    static void ReSizeGLScene(GLsizei width, GLsizei height);};#endif//CWindow.cpp:#include "CWindow.h"#include <gl\gl.h>			// Header File For The OpenGL32 Library#include <gl\glu.h>			// Header File For The GLu32 Library/*	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)	*/ CWindow::CWindow() {    hDC=NULL;		// Private GDI Device Context    hRC=NULL;		// Permanent Rendering Context    hWnd=NULL;		// Holds Our Window Handle    //hInstance;		// Holds The Instance Of The Application}    BOOL CWindow::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) StaticWndProc;					// 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								this)))								//  Pass this class 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 CWindow::StaticWndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam){CWindow* pParent;   // Get pointer to window   if(uMsg == WM_CREATE)   {      pParent = (CWindow*)((LPCREATESTRUCT)lParam)->lpCreateParams;      SetWindowLongPtr(hWnd,GWL_USERDATA,(LONG_PTR)pParent);   }   else   {      pParent = (CWindow*)GetWindowLongPtr(hWnd,GWL_USERDATA);      if(!pParent) return DefWindowProc(hWnd,uMsg,wParam,lParam);   }   pParent->hWnd = hWnd;   return pParent->WndProc(uMsg,wParam,lParam);}GLvoid CWindow::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	}	//standardFont.KillFont();						// Destroy The Font	}LRESULT CWindow::WndProc(				// 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 CWindow::InitGL(GLvoid)										// All Setup For OpenGL Goes Here{	glEnable(GL_TEXTURE_2D);							// Enable Texture Mapping ( NEW )	//glShadeModel(GL_SMOOTH);							// Enable Smooth Shading	glClearColor(0.0f, 0.0f, 0.5f, 0.0f);				// 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	quadratic=gluNewQuadric();							// Create A Pointer To The Quadric Object (Return 0 If No Memory)	gluQuadricNormals(quadratic, GLU_SMOOTH);			// Create Smooth Normals 	gluQuadricTexture(quadratic, GL_TRUE);				// Create Texture Coords   /*	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);	// Clear The Screen And The Depth Buffer	glLoadIdentity();	glTranslatef(0,0,-1);    glRasterPos2f(-0.2,0);    glPrint("LOADING...");  */  return TRUE;}void CWindow::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}

LRESULT CALLBACK (*WndProc)(HWND, UINT, WPARAM, LPARAM);