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endasil

OpenGL having some problem with wglUseFontBitmaps

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Have the function build font that i gotten from NEHEs tutorial page when i'm trying to use it in my project all i get is black screen. if i add these rows HGLRC hglrc = wglCreateContext(*mHDC); wglMakeCurrent(*mHDC, hglrc); The font will appear. So it feels like what the hdc points to isn't the one used for some strange reason. I can't understand what i have done wrong. Very thankful if someone would like to help me Create bitmap function

CBitmapFont::CBitmapFont(HDC *hdc,int fontSize)
{
		mHDC = hdc;
		BuildFont(fontSize);
}


GLvoid CBitmapFont::BuildFont( int fontSize ) // Build Our Bitmap Font
{
	HGLRC hglrc = wglCreateContext(*mHDC);
	wglMakeCurrent(*mHDC, hglrc);


	assert(mHDC != NULL);
	HFONT	font;										// Windows Font ID
	HFONT	oldfont;									// Used For Good House Keeping

	base = glGenLists(96);								// Storage For 96 Characters

	font = CreateFont(fontSize,							// Height Of Font
		0,								// Width Of Font
		0,								// Angle Of Escapement
		0,								// Orientation Angle
		FW_NORMAL,						// 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
		"Courier New");					// Font Name

	assert(font !=NULL);
	oldfont = (HFONT)SelectObject(*mHDC, font);           // Selects The Font We Want
	assert(oldfont != NULL);
	assert(oldfont != HGDI_ERROR );
	HRESULT result = wglUseFontBitmaps(*mHDC, 32, 96, base);				// Builds 96 Characters Starting At Character 32
	
	if(result != true)
	{	
		TCHAR szBuf[80]; 
		LPVOID lpMsgBuf;
		DWORD dw = GetLastError(); 

		FormatMessage(
			FORMAT_MESSAGE_ALLOCATE_BUFFER | 
			FORMAT_MESSAGE_FROM_SYSTEM,
			NULL,
			dw,
			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
			(LPTSTR) &lpMsgBuf,
			0, NULL );

		wsprintf(szBuf, 
			"failed with error %d: %s", dw, lpMsgBuf); 

		MessageBox(NULL, szBuf, "Error", MB_OK); 


		LocalFree(lpMsgBuf);


	}


	assert(result != false);
	HGDIOBJ myresult = SelectObject(*mHDC, oldfont);							// Selects The Font We Want
	DeleteObject(font);									// Delete The Font
}
Create window and initialize OpenGL

GLint CGame::initialize(HINSTANCE hInstance, bool bFullScreen, int iWidth, GLint iHeight)
{

	if(createWindow(hInstance, bFullScreen, iWidth, iHeight) == 0)
		return 0;

	// -------------------------------------
	// Configure the pixel format.
	// -------------------------------------

	setupPixelFormat(&mHDC);

	// -------------------------------------
	// Create a rendering context.
	// -------------------------------------

	m_HGLRC = wglCreateContext(mHDC);
                assert(m_HGLRC != NULL);

	// -------------------------------------
	// Make it current
	// -------------------------------------

	wglMakeCurrent(mHDC, m_HGLRC);


	// -------------------------------------
	// Clear The Stencil Buffer To 0
	// -------------------------------------

	glClearStencil(0);

	// -------------------------------------
	//Initialize the OpenGL bit.
	// -------------------------------------

	glViewport(0, 0, m_width, m_height);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glEnable(GL_DEPTH_TEST);

	gluPerspective(60, //view angle
		(float) m_width / m_height,	//aspect ratio
		0.1, //near clip
		900.0);//far clip

	glMatrixMode(GL_MODELVIEW);

	glLoadIdentity();

	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);	
	m_PPMObject.load("wood2.ppm");
	glGenTextures(1, &m_texName);
	glBindTexture(GL_TEXTURE_2D, m_texName);

	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

	glTexImage2D(GL_TEXTURE_2D, 0,GL_RGB, m_PPMObject.getWidth(), m_PPMObject.getHeight(),0,GL_RGB,GL_UNSIGNED_BYTE, m_PPMObject.getData());


	initializeLight();

	glEnable(GL_TEXTURE_2D);


	mBMPFont = new CBitmapFont(&mHDC,90);


	return 1;
}

Create a window

int CGame::createWindow(HINSTANCE hInstance, bool bFullScreen, int iWidth, GLint iHeight)
{
	m_width = iWidth;
	m_height = iHeight;
	m_fullscreen = bFullScreen;

	m_MyWindow.cbSize = sizeof(WNDCLASSEX);
	m_MyWindow.lpfnWndProc = CGame::myEventHandler;
	m_MyWindow.style = CS_HREDRAW | CS_VREDRAW;
	m_MyWindow.cbClsExtra = 0;
	m_MyWindow.cbWndExtra = 0;
	m_MyWindow.hInstance = hInstance;
	m_MyWindow.hIcon = LoadIcon(NULL, IDI_APPLICATION);
	m_MyWindow.hCursor = LoadCursor(NULL, IDC_ARROW);
	m_MyWindow.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
	m_MyWindow.lpszMenuName = NULL;
	m_MyWindow.lpszClassName = _T("myWin");
	m_MyWindow.hIconSm = LoadIcon(NULL, IDI_APPLICATION);


	// ---------------------------------------------------
	// Registration of the window.
	// ---------------------------------------------------

	if(RegisterClassEx(&m_MyWindow) == 0)
	{
		return 0;
	}


	if(m_fullscreen == true)
	{	


		// ---------------------------------------------------
		// Configure the style, no boarders wanted for the 
		// window.
		// ---------------------------------------------------

		m_style = WS_POPUP | WS_CLIPSIBLINGS | WS_CLIPCHILDREN;		


		// -----------------------------------------------
		// Before creating a window, we need to 
		// configure the display settings. "settings
		// is used ot keep informaiton about the display
		// -----------------------------------------------

		DEVMODE settings; 

		// -----------------------------------------------
		// Clean the setting variable
		// -----------------------------------------------

		memset(&settings, 0, sizeof(settings));


		// -----------------------------------------------
		// Get info display settings information
		// -----------------------------------------------

		if( !(EnumDisplaySettings(NULL, ENUM_CURRENT_SETTINGS, &settings)) )
		{
			MessageBox(NULL, _T("Could not get display-settings"), 
				_T("Oooupss!!"), MB_OK | MB_ICONEXCLAMATION);

			return 0;
		}

		// -----------------------------------------------
		// Set resolution and BPS
		// -----------------------------------------------

		settings.dmPelsWidth = m_width;
		settings.dmPelsHeight = m_height;
		settings.dmBitsPerPel = 32;


		// -----------------------------------------------
		// Change the display settings and get
		// rid of the taskbar.
		// -----------------------------------------------

		GLint resultat = ChangeDisplaySettings(&settings,CDS_FULLSCREEN);

		if(resultat != DISP_CHANGE_SUCCESSFUL)
		{
			MessageBox(NULL, _T("Kunde inte ändra display-settings"), 
				_T("Oooupss!!"), MB_OK | MB_ICONEXCLAMATION);			
			return 0;
		}

		// -----------------------------------------------
		// Hide the mouse cursor.
		// -----------------------------------------------

		ShowCursor(false);
	}
	else
	{

		// -----------------------------------------------
		// We want tot create a normal window
		// -----------------------------------------------

		m_style = WS_OVERLAPPEDWINDOW | WS_CLIPSIBLINGS | WS_CLIPCHILDREN;


		m_fullscreen = false;
	}


	// -------------------------------------
	// Use a rect with the same size as the 
	// requested size
	// -------------------------------------

	RECT theWindow;
	theWindow.left	= 0;								
	theWindow.right	= m_width;							
	theWindow.top = 0;								
	theWindow.bottom = m_height;							

	// -------------------------------------
	// Calculate the required size of the
	// window rectangle  based on the desired 
	// client-rectangle size. 
	// -------------------------------------

	AdjustWindowRect( &theWindow, m_style, false);		


	// -------------------------------------
	// Now create the window.
	// -------------------------------------

	m_hMyWnd = CreateWindowEx(NULL,
		_T("myWin"), 
		_T("Linewars 3D"), 
		m_style, 
		0, 0, theWindow.right - theWindow.left, //width of window
		theWindow.bottom - theWindow.top,       //height of window
		NULL, 
		NULL, 
		hInstance, 
		NULL);

	// -------------------------------------
	// Show and draw the window
	// -------------------------------------

	ShowWindow(m_hMyWnd, SW_SHOWNORMAL);			
	UpdateWindow(m_hMyWnd);							



	// -------------------------------------
	// Get the windows Device context
	// -------------------------------------


	if (!(mHDC=GetDC(m_hMyWnd)))							// Did We Get A Device Context?
	{
		
		MessageBox(NULL,"Can't Create A GL Device Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE
	}


	return 1;
}

void CGame::setupPixelFormat(HDC *dc)
{
	PIXELFORMATDESCRIPTOR pfd = {
		sizeof(PIXELFORMATDESCRIPTOR),
		1,
		PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER,
		PFD_TYPE_RGBA,
		32,
		0, 0, 0, 0, 0, 0,
		0,
		0,
		0,
		0, 0, 0, 0,
		32,
		0,		 // Turn off stencil buffer.
		0,
		PFD_MAIN_PLANE,
		0,
		0, 0, 0};


		// -------------------------------------------
		// Select the best pixel format
		// -------------------------------------------

		int pixelformat = ChoosePixelFormat(*dc, &pfd);


		// -------------------------------------------
		// Turn on the selected format.
		// -------------------------------------------

		SetPixelFormat(*dc, pixelformat, &pfd);
}



[Edited by - endasil on March 18, 2007 3:05:23 PM]

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mHDC is definitely the problem. It's hard to see what it even is, i'm guessing some global CDC or this wouldn't compile. Be sure that the CDC is actually the windows DC or at leasts shares memory with it (wglShareLists), or the display lists for the fonts will not be available.

We would need to see the window creation code before we would know why your DC is not receiving OpenGL calls.

If you're getting a black screen, then you probably have the right DC, try changing clear colors to verify this. Always remember to disable texturing, lighting and depth testing when using fonts.

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the window creation code is listed. Look for this:

int CGame::createWindow(HINSTANCE hInstance, bool bFullScreen, int iWidth, GLint iHeight)


Sorry if the post is a bit caothic, if you got suggestions on how i could make it clearer and easier to read i would be happy to change it.


Oh, and you said "Always remember to disable texturing, lighting and depth testing when using fonts."

You mean that i should disable it before printing the font on screen and then eanble it afterwards?

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Guest Anonymous Poster
Click edit in the top right of your original post and put your code in source brackets please!

[ source]
//Code here.
[ /source]

Just remove the spaces.

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Make sure you shutdown texture before you render your text and then you can reenable it after you render the text. You should post your rendering function. You can try and set your color to white with glColor3f(1.0f, 1.0f, 1.0f) and see if that works.

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