• Advertisement
Sign in to follow this  

OpenGL having some problem with wglUseFontBitmaps

This topic is 3991 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

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]

Share this post


Link to post
Share on other sites
Advertisement
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.

Share this post


Link to post
Share on other sites
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?

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
  • Advertisement
  • Popular Tags

  • Advertisement
  • Popular Now

  • Similar Content

    • By LifeArtist
      Good Evening,
      I want to make a 2D game which involves displaying some debug information. Especially for collision, enemy sights and so on ...
      First of I was thinking about all those shapes which I need will need for debugging purposes: circles, rectangles, lines, polygons.
      I am really stucked right now because of the fundamental question:
      Where do I store my vertices positions for each line (object)? Currently I am not using a model matrix because I am using orthographic projection and set the final position within the VBO. That means that if I add a new line I would have to expand the "points" array and re-upload (recall glBufferData) it every time. The other method would be to use a model matrix and a fixed vbo for a line but it would be also messy to exactly create a line from (0,0) to (100,20) calculating the rotation and scale to make it fit.
      If I proceed with option 1 "updating the array each frame" I was thinking of having 4 draw calls every frame for the lines vao, polygons vao and so on. 
      In addition to that I am planning to use some sort of ECS based architecture. So the other question would be:
      Should I treat those debug objects as entities/components?
      For me it would make sense to treat them as entities but that's creates a new issue with the previous array approach because it would have for example a transform and render component. A special render component for debug objects (no texture etc) ... For me the transform component is also just a matrix but how would I then define a line?
      Treating them as components would'nt be a good idea in my eyes because then I would always need an entity. Well entity is just an id !? So maybe its a component?
      Regards,
      LifeArtist
    • By QQemka
      Hello. I am coding a small thingy in my spare time. All i want to achieve is to load a heightmap (as the lowest possible walking terrain), some static meshes (elements of the environment) and a dynamic character (meaning i can move, collide with heightmap/static meshes and hold a varying item in a hand ). Got a bunch of questions, or rather problems i can't find solution to myself. Nearly all are deal with graphics/gpu, not the coding part. My c++ is on high enough level.
      Let's go:
      Heightmap - i obviously want it to be textured, size is hardcoded to 256x256 squares. I can't have one huge texture stretched over entire terrain cause every pixel would be enormous. Thats why i decided to use 2 specified textures. First will be a tileset consisting of 16 square tiles (u v range from 0 to 0.25 for first tile and so on) and second a 256x256 buffer with 0-15 value representing index of the tile from tileset for every heigtmap square. Problem is, how do i blend the edges nicely and make some computationally cheap changes so its not obvious there are only 16 tiles? Is it possible to generate such terrain with some existing program?
      Collisions - i want to use bounding sphere and aabb. But should i store them for a model or entity instance? Meaning i have 20 same trees spawned using the same tree model, but every entity got its own transformation (position, scale etc). Storing collision component per instance grats faster access + is precalculated and transformed (takes additional memory, but who cares?), so i stick with this, right? What should i do if object is dynamically rotated? The aabb is no longer aligned and calculating per vertex min/max everytime object rotates/scales is pretty expensive, right?
      Drawing aabb - problem similar to above (storing aabb data per instance or model). This time in my opinion per model is enough since every instance also does not have own vertex buffer but uses the shared one (so 20 trees share reference to one tree model). So rendering aabb is about taking the model's aabb, transforming with instance matrix and voila. What about aabb vertex buffer (this is more of a cosmetic question, just curious, bumped onto it in time of writing this). Is it better to make it as 8 points and index buffer (12 lines), or only 2 vertices with min/max x/y/z and having the shaders dynamically generate 6 other vertices and draw the box? Or maybe there should be just ONE 1x1x1 cube box template moved/scaled per entity?
      What if one model got a diffuse texture and a normal map, and other has only diffuse? Should i pass some bool flag to shader with that info, or just assume that my game supports only diffuse maps without fancy stuff?
      There were several more but i forgot/solved them at time of writing
      Thanks in advance
    • By RenanRR
      Hi All,
      I'm reading the tutorials from learnOpengl site (nice site) and I'm having a question on the camera (https://learnopengl.com/Getting-started/Camera).
      I always saw the camera being manipulated with the lookat, but in tutorial I saw the camera being changed through the MVP arrays, which do not seem to be camera, but rather the scene that changes:
      Vertex Shader:
      #version 330 core layout (location = 0) in vec3 aPos; layout (location = 1) in vec2 aTexCoord; out vec2 TexCoord; uniform mat4 model; uniform mat4 view; uniform mat4 projection; void main() { gl_Position = projection * view * model * vec4(aPos, 1.0f); TexCoord = vec2(aTexCoord.x, aTexCoord.y); } then, the matrix manipulated:
      ..... glm::mat4 projection = glm::perspective(glm::radians(fov), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f); ourShader.setMat4("projection", projection); .... glm::mat4 view = glm::lookAt(cameraPos, cameraPos + cameraFront, cameraUp); ourShader.setMat4("view", view); .... model = glm::rotate(model, glm::radians(angle), glm::vec3(1.0f, 0.3f, 0.5f)); ourShader.setMat4("model", model);  
      So, some doubts:
      - Why use it like that?
      - Is it okay to manipulate the camera that way?
      -in this way, are not the vertex's positions that changes instead of the camera?
      - I need to pass MVP to all shaders of object in my scenes ?
       
      What it seems, is that the camera stands still and the scenery that changes...
      it's right?
       
       
      Thank you
       
    • By dpadam450
      Sampling a floating point texture where the alpha channel holds 4-bytes of packed data into the float. I don't know how to cast the raw memory to treat it as an integer so I can perform bit-shifting operations.

      int rgbValue = int(textureSample.w);//4 bytes of data packed as color
      // algorithm might not be correct and endianness might need switching.
      vec3 extractedData = vec3(  rgbValue & 0xFF000000,  (rgbValue << 8) & 0xFF000000, (rgbValue << 16) & 0xFF000000);
      extractedData /= 255.0f;
    • By Devashish Khandelwal
      While writing a simple renderer using OpenGL, I faced an issue with the glGetUniformLocation function. For some reason, the location is coming to be -1.
      Anyone has any idea .. what should I do?
  • Advertisement