Jeff Molofee - NeHe's OpenGL Tutorials

#include // Header File For Windows

#include // Header File For Windows Math Library ( ADD )

#include // Header File For Standard Input/Output ( ADD )

#include // Header File For Variable Argument Routines ( ADD )

#include // Header File For The OpenGL32 Library

#include // Header File For The GLu32 Library

#include // Header File For The GLaux Library

HDC hDC=NULL; // Private GDI Device Context

HGLRC hRC=NULL; // Permanent Rendering Context

HWND hWnd=NULL; // Holds Our Window Handle

HINSTANCE hInstance; // Holds The Instance Of The Application

We're going to add 2 new variables. base will hold the number of the first display list we create. Each character requires it's own display list. The character 'A' is 65 in the display list, 'B' is 66, 'C' is 67, etc. So 'A' would be stored in display list base+65.

Next we add a variable called rot. rot will be used to spin the text around on the screen using both SIN and COS. It will also be used to pulse the colors.

GLuint base; // Base Display List For The Font Set ( ADD )

GLfloat rot; // Used To Rotate The Text ( ADD )

bool keys[256]; // Array Used For The Keyboard Routine

bool active=TRUE; // Window Active Flag Set To TRUE By Default

bool fullscreen=TRUE; // Fullscreen Flag Set To Fullscreen Mode By Default

GLYPHMETRICSFLOAT gmf[256] will hold information about the placement and orientation for each of our 256 outline font display lists. We select a letter by using gmf[num]. num is the number of the display list we want to know something about. Later in the code I'll show you how to find out the width of each character so that you can automatically center the text on the screen. Keep in mind that each character can be a different width. glyphmetrics will make our lives a whole lot easier.

GLYPHMETRICSFLOAT gmf[256]; // Storage For Information About Our Font

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); // Declaration For WndProc

The following section of code builds the actual font similar to the way we made our Bitmap font. Just like in lesson 13, this section of code was the hardest part for me to figure out.

'HFONT font' will hold our Windows font ID.

Next we define base. We do this by creating a group of 256 display lists using glGenLists(256). After the display lists are created, the variable base will hold the number of the first list.

GLvoid BuildFont(GLvoid) // Build Our Bitmap Font

{

HFONT font; // Windows Font ID

base = glGenLists(256); // Storage For 256 Characters

More fun stuff. We're going to create our Outline font. We start off by specifying the size of the font. You'll notice it's a negative number. By putting a minus, we're telling windows to find us a font based on the CHARACTER height. If we use a positive number we match the font based on the CELL height.

font = CreateFont(–12, // Height Of Font

Then we specify the cell width. You'll notice I have it set to 0. By setting values to 0, windows will use the default value. You can play around with this value if you want. Make the font wide, etc.

0, // Width Of Font

Angle of Escapement will rotate the font. Orientation Angle quoted from MSDN help Specifies the angle, in tenths of degrees, between each character's base line and the x-axis of the device. Unfortunately I have no idea what that means :(

0, // Angle Of Escapement

0, // Orientation Angle

Font weight is a great parameter. You can put a number from 0–1000 or you can use one of the predefined values. FW_DONTCARE is 0, FW_NORMAL is 400, FW_BOLD is 700 and FW_BLACK is 900. There are alot more predefined values, but those 4 give some good variety. The higher the value, the thicker the font (more bold).

FW_BOLD, // Font Weight

Italic, Underline and Strikeout can be either TRUE or FALSE. Basically if underline is TRUE, the font will be underlined. If it's FALSE it wont be. Pretty simple :)

FALSE, // Italic

FALSE, // Underline

FALSE, // Strikeout

Character set Identifier describes the type of Character set you wish to use. There are too many types to explain. CHINESEBIG5_CHARSET, GREEK_CHARSET, RUSSIAN_CHARSET, DEFAULT_CHARSET, etc. ANSI is the one I use, although DEFAULT would probably work just as well.

If you're interested in using a font such as Webdings or Wingdings, you need to use SYMBOL_CHARSET instead of ANSI_CHARSET.

ANSI_CHARSET, // Character Set Identifier

Output Precision is very important. It tells Windows what type of character set to use if there is more than one type available. OUT_TT_PRECIS tells Windows that if there is more than one type of font to choose from with the same name, select the TRUETYPE version of the font. Truetype fonts always look better, especially when you make them large. You can also use OUT_TT_ONLY_PRECIS, which ALWAYS trys to use a TRUETYPE Font.

OUT_TT_PRECIS, // Output Precision

Clipping Precision is the type of clipping to do on the font if it goes outside the clipping region. Not much to say about this, just leave it set to default.

CLIP_DEFAULT_PRECIS, // Clipping Precision

Output Quality is very important.you can have PROOF, DRAFT, NONANTIALIASED, DEFAULT or ANTIALIASED. We all know that ANTIALIASED fonts look good :) Antialiasing a font is the same effect you get when you turn on font smoothing in Windows. It makes everything look less jagged.

ANTIALIASED_QUALITY, // Output Quality

Next we have the Family and Pitch settings. For pitch you can have DEFAULT_PITCH, FIXED_PITCH and VARIABLE_PITCH, and for family you can have FF_DECORATIVE, FF_MODERN, FF_ROMAN, FF_SCRIPT, FF_SWISS, FF_DONTCARE. Play around with them to find out what they do. I just set them both to default.

FF_DONTCARE|DEFAULT_PITCH, // Family And Pitch

Finally… We have the actual name of the font. Boot up Microsoft Word or some other text editor. Click on the font drop down menu, and find a font you like. To use the font, replace 'Comic Sans MS' with the name of the font you'd rather use.

"Comic Sans MS"); // Font Name

Now we select the font by relating it to our DC.

SelectObject(hDC, font); // Selects The Font We Created

Now for the new code. We build our Outline font using a new command wglUseFontOutlines. We select our DC, the starting character, the number of characters to create and the 'base' display list value. All very similar to the way we built our Bitmap font.

wglUseFontOutlines(hDC, // Select The Current DC

0, // Starting Character

255, // Number Of Display Lists To Build

base, // Starting Display Lists

That's not all however. We then set the deviation level. The closer to 0.0f, the smooth the font will look. After we set the deviation, we get to set the font thickness. This describes how thick the font is on the Z axis. 0.0f will produce a flat 2D looking font and 1.0f will produce a font with some depth.

The parameter WGL_FONT_POLYGONS tells OpenGL to create a solid font using polygons. If we use WGL_FONT_LINES instead, the font will be wireframe (made of lines). It's also important to note that if you use GL_FONT_LINES, normals will not be generated so lighting will not work properly.

The last parameter gmf points to the address buffer for the display list data.