本文共 12782 字，大约阅读时间需要 42 分钟。

(此节内容对应NEHE教程第17课)

前面2节所创建的字体。都是需要结合OS

其实原理很简单，每个字符对应都是一个四边形，我们对这个四边形进行纹理贴图（贴图内容为字符），每次输出字符的时候的，等于找到对应的纹理图形 显示出来即可，为了提高性能，我们将使用显示列表

#include "header.h""HDC			hDC=NULL;		HGLRC		hRC=NULL;		HWND		hWnd=NULL;		HINSTANCE	hInstance;		bool	keys[256];			bool	active=TRUE;		bool	fullscreen=TRUE;	GLuint	base;				GLuint	texture[2];			GLuint	loop;				GLfloat	cnt1;				GLfloat	cnt2;				LRESULT	CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);	AUX_RGBImageRec *LoadBMP(char *Filename)                {        FILE *File=NULL;                                        if (!Filename)                                         {                return NULL;                                    }        File=fopen(Filename,"r");                               if (File)                                               {                fclose(File);                                           return auxDIBImageLoad(Filename);               }        return NULL;                                    }int LoadGLTextures()                                   {        int Status=FALSE;                                     AUX_RGBImageRec *TextureImage[2];                       memset(TextureImage,0,sizeof(void *)*2);               if ((TextureImage[0]=LoadBMP("Data/Font.bmp")) &&			(TextureImage[1]=LoadBMP("Data/Bumps.bmp")))        {                Status=TRUE;                                            glGenTextures(2, &texture[0]);         				for (loop=0; loop<2; loop++)				{	                glBindTexture(GL_TEXTURE_2D, texture[loop]);			        glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);				    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);					glTexImage2D(GL_TEXTURE_2D, 0, 3, TextureImage[loop]->sizeX, TextureImage[loop]->sizeY, 0, 						GL_RGB, GL_UNSIGNED_BYTE, TextureImage[loop]->data);				}        }		for (loop=0; loop<2; loop++)		{	        if (TextureImage[loop])									    {			        if (TextureImage[loop]->data)							    {					        free(TextureImage[loop]->data);						}					free(TextureImage[loop]);							}		}        return Status;                                 }GLvoid BuildFont(GLvoid)								{	float	cx;												float	cy;												base=glGenLists(256);									glBindTexture(GL_TEXTURE_2D, texture[0]);				for (loop=0; loop<256; loop++)							{		cx=float(loop%16)/16.0f;								cy=float(loop/16)/16.0f;								glNewList(base+loop,GL_COMPILE);							glBegin(GL_QUADS);											glTexCoord2f(cx,1-cy-0.0625f);							glVertex2i(0,0);										glTexCoord2f(cx+0.0625f,1-cy-0.0625f);					glVertex2i(16,0);										glTexCoord2f(cx+0.0625f,1-cy);							glVertex2i(16,16);										glTexCoord2f(cx,1-cy);									glVertex2i(0,16);									glEnd();												glTranslated(10,0,0);								glEndList();										}												}GLvoid KillFont(GLvoid)									{	glDeleteLists(base,256);							}GLvoid glPrint(GLint x, GLint y, char *string, int set)	{	if (set>1)	{		set=1;	}	glBindTexture(GL_TEXTURE_2D, texture[0]);				glDisable(GL_DEPTH_TEST);								glMatrixMode(GL_PROJECTION);							glPushMatrix();											glLoadIdentity();										glOrtho(0,640,0,480,-1,1);								glMatrixMode(GL_MODELVIEW);								glPushMatrix();											glLoadIdentity();										glTranslated(x,y,0);									glListBase(base-32+(128*set));							glCallLists(strlen(string),GL_UNSIGNED_BYTE,string);	glMatrixMode(GL_PROJECTION);							glPopMatrix();											glMatrixMode(GL_MODELVIEW);								glPopMatrix();											glEnable(GL_DEPTH_TEST);							}GLvoid ReSizeGLScene(GLsizei width, GLsizei height)		{	if (height==0)											{		height=1;											}	glViewport(0,0,width,height);							glMatrixMode(GL_PROJECTION);							glLoadIdentity();										gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.1f,100.0f);		glMatrixMode(GL_MODELVIEW);								glLoadIdentity();									}int InitGL(GLvoid)										{	if (!LoadGLTextures())									{		return FALSE;										}	BuildFont();											glClearColor(0.0f, 0.0f, 0.0f, 0.0f);					glClearDepth(1.0);										glDepthFunc(GL_LEQUAL);									glBlendFunc(GL_SRC_ALPHA,GL_ONE);						glShadeModel(GL_SMOOTH);								glEnable(GL_TEXTURE_2D);								return TRUE;										}int DrawGLScene(GLvoid)									{	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);		glLoadIdentity();									glBindTexture(GL_TEXTURE_2D, texture[1]);				glTranslatef(0.0f,0.0f,-5.0f);						glRotatef(45.0f,0.0f,0.0f,1.0f);						glRotatef(cnt1*30.0f,1.0f,1.0f,0.0f);					glDisable(GL_BLEND);								glColor3f(1.0f,1.0f,1.0f);								glBegin(GL_QUADS);										glTexCoord2d(0.0f,0.0f);								glVertex2f(-1.0f, 1.0f);							glTexCoord2d(1.0f,0.0f);								glVertex2f( 1.0f, 1.0f);								glTexCoord2d(1.0f,1.0f);								glVertex2f( 1.0f,-1.0f);								glTexCoord2d(0.0f,1.0f);								glVertex2f(-1.0f,-1.0f);							glEnd();												glRotatef(90.0f,1.0f,1.0f,0.0f);						glBegin(GL_QUADS);										glTexCoord2d(0.0f,0.0f);								glVertex2f(-1.0f, 1.0f);							glTexCoord2d(1.0f,0.0f);								glVertex2f( 1.0f, 1.0f);								glTexCoord2d(1.0f,1.0f);								glVertex2f( 1.0f,-1.0f);								glTexCoord2d(0.0f,1.0f);								glVertex2f(-1.0f,-1.0f);						glEnd();												glEnable(GL_BLEND);										glLoadIdentity();											glColor3f(1.0f*float(cos(cnt1)),1.0f*float(sin(cnt2)),1.0f-0.5f*float(cos(cnt1+cnt2)));	glPrint(int((280+250*cos(cnt1))),int(235+200*sin(cnt2)),"NeHe",0);			glColor3f(1.0f*float(sin(cnt2)),1.0f-0.5f*float(cos(cnt1+cnt2)),1.0f*float(cos(cnt1)));	glPrint(int((280+230*cos(cnt2))),int(235+200*sin(cnt1)),"OpenGL",1);		glColor3f(0.0f,0.0f,1.0f);								glPrint(int(240+200*cos((cnt2+cnt1)/5)),2,"Giuseppe D'Agata",0);	glColor3f(1.0f,1.0f,1.0f);							glPrint(int(242+200*cos((cnt2+cnt1)/5)),2,"Giuseppe D'Agata",0);	cnt1+=0.01f;										cnt2+=0.0081f;										return TRUE;									}GLvoid KillGLWindow(GLvoid)								{	if (fullscreen)											{		ChangeDisplaySettings(NULL,0);							ShowCursor(TRUE);									}	if (hRC)												{		if (!wglMakeCurrent(NULL,NULL))							{			MessageBox(NULL,"Release Of DC And RC Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);		}		if (!wglDeleteContext(hRC))								{			MessageBox(NULL,"Release Rendering Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);		}		hRC=NULL;											}	if (hDC && !ReleaseDC(hWnd,hDC))						{		MessageBox(NULL,"Release Device Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);		hDC=NULL;											}	if (hWnd && !DestroyWindow(hWnd))					{		MessageBox(NULL,"Could Not Release hWnd.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);		hWnd=NULL;											}	if (!UnregisterClass("OpenGL",hInstance))				{		MessageBox(NULL,"Could Not Unregister Class.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);		hInstance=NULL;									// Set hInstance To NULL	}	KillFont();											// Kill The Font}BOOL CreateGLWindow(char* title, int width, int height, int bits, bool fullscreenflag){	GLuint		PixelFormat;				WNDCLASS	wc;							DWORD		dwExStyle;					DWORD		dwStyle;					RECT		WindowRect;					WindowRect.left=(long)0;				WindowRect.right=(long)width;			WindowRect.top=(long)0;					WindowRect.bottom=(long)height;			fullscreen=fullscreenflag;			hInstance			= GetModuleHandle(NULL);					wc.style			= CS_HREDRAW | CS_VREDRAW | CS_OWNDC;		wc.lpfnWndProc		= (WNDPROC) WndProc;						wc.cbClsExtra		= 0;										wc.cbWndExtra		= 0;										wc.hInstance		= hInstance;								wc.hIcon			= LoadIcon(NULL, IDI_WINLOGO);				wc.hCursor			= LoadCursor(NULL, IDC_ARROW);				wc.hbrBackground	= NULL;										wc.lpszMenuName		= NULL;										wc.lpszClassName	= "OpenGL";									if (!RegisterClass(&wc))										{		MessageBox(NULL,"Failed To Register The Window Class.","ERROR",MB_OK|MB_ICONEXCLAMATION);		return FALSE;												}		if (fullscreen)													{		DEVMODE dmScreenSettings;										memset(&dmScreenSettings,0,sizeof(dmScreenSettings));			dmScreenSettings.dmSize=sizeof(dmScreenSettings);				dmScreenSettings.dmPelsWidth	= width;					dmScreenSettings.dmPelsHeight	= height;						dmScreenSettings.dmBitsPerPel	= bits;							dmScreenSettings.dmFields=DM_BITSPERPEL|DM_PELSWIDTH|DM_PELSHEIGHT;			if (ChangeDisplaySettings(&dmScreenSettings,CDS_FULLSCREEN)!=DISP_CHANGE_SUCCESSFUL)		{						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;					}			else			{				MessageBox(NULL,"Program Will Now Close.","ERROR",MB_OK|MB_ICONSTOP);				return FALSE;												}		}	}	if (fullscreen)													{		dwExStyle=WS_EX_APPWINDOW;										dwStyle=WS_POPUP;											ShowCursor(FALSE);										}	else	{		dwExStyle=WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;				dwStyle=WS_OVERLAPPEDWINDOW;							}	AdjustWindowRectEx(&WindowRect, dwStyle, FALSE, dwExStyle);			if (!(hWnd=CreateWindowEx(	dwExStyle,															"OpenGL",															title,																dwStyle |															WS_CLIPSIBLINGS |													WS_CLIPCHILDREN,													0, 0,																WindowRect.right-WindowRect.left,									WindowRect.bottom-WindowRect.top,									NULL,																NULL,																hInstance,														NULL)))									{		KillGLWindow();										MessageBox(NULL,"Window Creation Error.","ERROR",MB_OK|MB_ICONEXCLAMATION);		return FALSE;									}	static	PIXELFORMATDESCRIPTOR pfd=					{		sizeof(PIXELFORMATDESCRIPTOR),						1,													PFD_DRAW_TO_WINDOW |								PFD_SUPPORT_OPENGL |								PFD_DOUBLEBUFFER,									PFD_TYPE_RGBA,										bits,												0, 0, 0, 0, 0, 0,									0,												0,													0,													0, 0, 0, 0,											16,													0,												0,													PFD_MAIN_PLANE,										0,												0, 0, 0											};		if (!(hDC=GetDC(hWnd)))								{		KillGLWindow();									MessageBox(NULL,"Can't Create A GL Device Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);		return FALSE;									}	if (!(PixelFormat=ChoosePixelFormat(hDC,&pfd)))		{		KillGLWindow();										MessageBox(NULL,"Can't Find A Suitable PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);		return FALSE;									}	if(!SetPixelFormat(hDC,PixelFormat,&pfd))			{		KillGLWindow();									MessageBox(NULL,"Can't Set The PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);		return FALSE;									}	if (!(hRC=wglCreateContext(hDC)))					{		KillGLWindow();									MessageBox(NULL,"Can't Create A GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);		return FALSE;									}	if(!wglMakeCurrent(hDC,hRC))					{		KillGLWindow();									MessageBox(NULL,"Can't Activate The GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);		return FALSE;								}	ShowWindow(hWnd,SW_SHOW);							SetForegroundWindow(hWnd);							SetFocus(hWnd);										ReSizeGLScene(width, height);						if (!InitGL())										{		KillGLWindow();									MessageBox(NULL,"Initialization Failed.","ERROR",MB_OK|MB_ICONEXCLAMATION);		return FALSE;								}	return TRUE;									}LRESULT CALLBACK WndProc(	HWND	hWnd,										UINT	uMsg,									WPARAM	wParam,										LPARAM	lParam)			{	switch (uMsg)										{		case WM_ACTIVATE:									{			if (!HIWORD(wParam))								{				active=TRUE;									}			else			{				active=FALSE;									}			return 0;										}		case WM_SYSCOMMAND:									{			switch (wParam)										{				case SC_SCREENSAVE:									case SC_MONITORPOWER:								return 0;										}			break;											}		case WM_CLOSE:										{			PostQuitMessage(0);									return 0;										}		case WM_KEYDOWN:									{			keys[wParam] = TRUE;								return 0;										}		case WM_KEYUP:										{			keys[wParam] = FALSE;								return 0;										}		case WM_SIZE:									{			ReSizeGLScene(LOWORD(lParam),HIWORD(lParam));  			return 0;										}	}	return DefWindowProc(hWnd,uMsg,wParam,lParam);}int WINAPI WinMain(	HINSTANCE	hInstance,								HINSTANCE	hPrevInstance,						LPSTR		lpCmdLine,								int			nCmdShow)			{	MSG		msg;									BOOL	done=FALSE;										if (MessageBox(NULL,"Would You Like To Run In Fullscreen Mode?", "Start FullScreen?",MB_YESNO|MB_ICONQUESTION)==IDNO)	{		fullscreen=FALSE;								}	if (!CreateGLWindow("NeHe & Giuseppe D'Agata's 2D Font Tutorial",640,480,16,fullscreen))	{		return 0;										}	while(!done)										{		if (PeekMessage(&msg,NULL,0,0,PM_REMOVE))			{			if (msg.message==WM_QUIT)						{				done=TRUE;										}			else												{				TranslateMessage(&msg);								DispatchMessage(&msg);							}		}		else												{						if ((active && !DrawGLScene()) || keys[VK_ESCAPE])				{				done=TRUE;										}			else												{			}			if (keys[VK_F1])									{				keys[VK_F1]=FALSE;									KillGLWindow();										fullscreen=!fullscreen;												if (!CreateGLWindow("NeHe & Giuseppe D'Agata's 2D Font Tutorial",640,480,16,fullscreen))				{					return 0;										}			}		}	}	KillGLWindow();									return (msg.wParam);			}

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