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Multi-font use.

Started by August 08, 2002 01:49 PM
1 comment, last by Lomilar 22 years, 6 months ago
I am attempting to use multiple fonts in a program, but from what I can tell, it will only use the last font that I tried building. Here''s my font class. From what I can tell, I am guessing that when a font is ''selected'' as per within the Build() function, it will only use that font. I ask because I am working on a project where having a clean thin font and a bold ''status'' font would be advantageous. Thanks in advance. Oh, and feel free to rip off this class. It seems to work well. Replace aString with your favorite string class.
  class GLFont
{
public:
	GLFont(){}
	~GLFont()
	{
		glDeleteLists(base,256);
	}
	void Build(HDC hdc,const char* typeface,int height,int weight,bool italic = false,bool underline = false,bool strikethrough = false)
	{
		int charset;
		m_hdc = hdc;
		glDeleteLists(base,256);
		base = glGenLists(256);

		if (stricmp(typeface,"symbol") == 0)
			charset = SYMBOL_CHARSET;
		else
			charset = ANSI_CHARSET;

		fontid = CreateFont(height,0,0,0,weight,italic,underline,strikethrough,charset,OUT_TT_PRECIS,CLIP_DEFAULT_PRECIS,DRAFT_QUALITY,DEFAULT_PITCH,typeface);
      SelectObject(hdc,fontid);
		wglUseFontBitmaps(hdc,0,256,base);
		GetCharWidth(hdc,0,255,widths);
		this->height = height;
	}
   int Measure(aString str)
   {
      uint len = 0;
      for (uint i = 0;i < strlen(str);i++)
      {
         len += widths[str[i]];
      }
   }
	void Draw(aString str)
	{
		glPushAttrib(GL_LIST_BIT);
		glListBase(base);
		glCallLists((GLsizei)strlen(str),GL_UNSIGNED_BYTE,str);
		glPopAttrib();
	}
private:
   HDC m_hdc;
	HFONT fontid;
	GLuint base;
	int widths[256];
	int height;
};  
I had the same problem.
The problem has to do with the hdc you are using when creating the fonts. Try changing the following lines from hdc to m_hdc like so:

SelectObject(m_hdc,fontid);
wglUseFontBitmaps(m_hdc,0,256,base);
GetCharWidth(m_hdc,0,255,widths);

By using a global hdc you are only allowed to create one font at a time.
hope that helps
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quote:
Original post by adamxiii
The problem has to do with the hdc you are using when creating the fonts.


since you only have one dc for the entire program, i don''t see how using a global variable to reference it instead of a local one if going to affect anything.
quote:

By using a global hdc you are only allowed to create one font at a time.

you are always restricted to selecting one font in any dc at any time, but you don''t need a dc to create a font at all.

quote:
Original post by Lomilar
Here''s my font class.


you, however, didn''t provide any code to show how you managed multiple fonts in your application. copying nehe''s font creation code here tell us nothing why multiple fonts aren''t working for you.
quote:

From what I can tell, I am guessing that when a font is ''selected'' as per within the Build() function, it will only use that font.


this is correct. wglusefontbitmaps will use the currently selected font for its operation.
quote:

I ask because I am working on a project where having a clean thin font and a bold ''status'' font would be advantageous.


so select another font into the dc, and call wglusefontbitmaps again.
quote:

Oh, and feel free to rip off this class. It seems to work well.


why thanks, but no thanks.
quote:

fontid = CreateFont(height,0,0,0,weight,italic,underline,strikethrough,charset,OUT_TT_PRECIS,CLIP_DEFAULT_PRECIS,DRAFT_QUALITY,DEFAULT_PITCH,typeface);
SelectObject(hdc,fontid);
wglUseFontBitmaps(hdc,0,256,base);


have you thought about relesing resources occupied by the font? take another look at how nehe creates his fonts.

since you didn''t give any information that will help us tell you where you went wrong, i hacked together some code that draws text in two alternating fonts. the code is ugly because nehe uses a whole bunch of globals and a bit because he doesn''t have a timer class. so don''t copypaste it, understand what i''ve done and make a cleaner version.

code dump [modified lesson 13]:

  /* *		This Code Was Created By Jeff Molofee 2000 *		Modified by Shawn T. to handle (%3.2f, num) parameters. *		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 <math.h>			// Header File For Windows Math Library#include <stdio.h>			// Header File For Standard Input/Output#include <stdarg.h>			// Header File For Variable Argument Routines#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 LibraryHDC			hDC=NULL;		// Private GDI Device ContextHGLRC		hRC=NULL;		// Permanent Rendering ContextHWND		hWnd=NULL;		// Holds Our Window HandleHINSTANCE	hInstance;		// Holds The Instance Of The ApplicationGLuint	base, base2;				// Base Display List For The Font SetGLfloat	cnt1;				// 1st Counter Used To Move Text & For ColoringGLfloat	cnt2;				// 2nd Counter Used To Move Text & For Coloringbool	keys[256];			// Array Used For The Keyboard Routinebool	active=TRUE;		// Window Active Flag Set To TRUE By Defaultbool	fullscreen=TRUE;	// Fullscreen Flag Set To Fullscreen Mode By DefaultLRESULT	CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);	// Declaration For WndProcunsigned BuildFont(const char *name)								// Build Our Bitmap Font{	HFONT	font;										// Windows Font ID	HFONT	oldfont;									// Used For Good House Keeping	unsigned base = glGenLists(96);								// Storage For 96 Characters	font = CreateFont(	-24,							// Height Of Font						0,								// Width Of Font						0,								// Angle Of Escapement						0,								// Orientation Angle						FW_BOLD,						// Font Weight						FALSE,							// Italic						FALSE,							// Underline						FALSE,							// Strikeout						ANSI_CHARSET,					// Character Set Identifier						OUT_TT_PRECIS,					// Output Precision						CLIP_DEFAULT_PRECIS,			// Clipping Precision						ANTIALIASED_QUALITY,			// Output Quality						FF_DONTCARE|DEFAULT_PITCH,		// Family And Pitch						name);					// Font Name	oldfont = (HFONT)SelectObject(hDC, font);           // Selects The Font We Want	wglUseFontBitmaps(hDC, 32, 96, base);				// Builds 96 Characters Starting At Character 32	SelectObject(hDC, oldfont);							// Selects The Font We Want	DeleteObject(font);									// Delete The Font	return base;}GLvoid KillFont(GLvoid)									// Delete The Font List{	glDeleteLists(base, 96);							// Delete All 96 Characters}GLvoid glPrint(unsigned base, const char *fmt, ...)					// Custom GL "Print" Routine{	char		text[256];								// Holds Our String	va_list		ap;										// Pointer To List Of Arguments	if (fmt == NULL)									// If There''s No Text		return;											// Do Nothing	va_start(ap, fmt);									// Parses The String For Variables	    vsprintf(text, fmt, ap);						// And Converts Symbols To Actual Numbers	va_end(ap);											// Results Are Stored In Text	glPushAttrib(GL_LIST_BIT);							// Pushes The Display List Bits	glListBase(base - 32);								// Sets The Base Character to 32	glCallLists(strlen(text), GL_UNSIGNED_BYTE, text);	// Draws The Display List Text	glPopAttrib();										// Pops The Display List Bits}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	base = BuildFont("courier new");										// Build The Font	base2 = BuildFont("times new roman");										// Build The Font	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(0.0f,0.0f,-1.0f);						// Move One Unit Into The Screen	// Pulsing Colors Based On Text Position	glColor3f(1.0f*float(cos(cnt1)),1.0f*float(sin(cnt2)),1.0f-0.5f*float(cos(cnt1+cnt2)));	// Position The Text On The Screen	glRasterPos2f(-0.45f+0.05f*float(cos(cnt1)), 0.32f*float(sin(cnt2)));	unsigned base = ::base;	static count = 0;	if (((++count)/100)&1)		base = ::base2; 	glPrint(base, "Active OpenGL Text With NeHe - %7.2f", cnt1);	// Print GL Text To The Screen	cnt1+=0.051f;										// Increase The First Counter	cnt2+=0.005f;										// Increase The First Counter	return TRUE;										// Everything Went OK}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	}	KillFont();}/*	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 Bitmap Font 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 Bitmap Font Tutorial",640,480,16,fullscreen))				{					return 0;						// Quit If Window Was Not Created				}			}		}	}	// Shutdown	KillGLWindow();									// Kill The Window	return (msg.wParam);							// Exit The Program}  

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