lesson24.cpp

关于OpenGL的实例教程源代码

		MessageBox(NULL,"Could Not Unregister Class.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		hInstance=NULL;										// Set hInstance To NULL
	}

	KillFont();												// Kill The Font
}

/*	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												// Otherwise
			{
				// 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														// Otherwise
	{
		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
	{
		fullscreen=TRUE;
		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												// Otherwise
			{
				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
		}
	}

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

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 Token, Extensions, Scissoring & TGA Loading 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
			{
				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 Token, Extensions, Scissoring & TGA Loading Tutorial",640,480,16,fullscreen))
					{
						return 0;								// Quit If Window Was Not Created
					}
				}

				if (keys[VK_UP] && (scroll>0))					// Is Up Arrow Being Pressed?
				{
					scroll-=2;									// If So, Decrease 'scroll' Moving Screen Down
				}

				if (keys[VK_DOWN] && (scroll<32*(maxtokens-9)))	// Is Down Arrow Being Pressed?
				{
					scroll+=2;									// If So, Increase 'scroll' Moving Screen Up
				}
			}
		}
	}

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