Rendering Font in GLUT - 1

There are two ways to display text in GLUT. The first is using bitmap fonts -- unscalable and doesn’t response to modelview transform. My preferred way is stroke fonts -- fonts that are drawn from OpenGL primitives.

(i) To insert fonts in GLUT (see here for documentation)

void glutStrokeCharacter(void *font, int character);
font:

This method can handle two types of font (first argument), namely

GLUT_STROKE_ROMAN
GLUT_STROKE_MONO_ROMAN

The MONO version is a fixed-width font (like Courier New, etc)

character:

Takes in any ASCII character from 32 through 127

(ii) To get the measurement of its length

int glutStrokeLength(void *font, const unsigned char *string);

This method returns the width in units from the unscaled modeling units


This is how to use them:
(1) Define a string generator function
This function serves to render the string being passed to it.

void renderStrokeString( void *font, const string& str )

{
for (int i = 0; i < str.length(); i++)
glutStrokeCharacter(font, str[i]);
}

(2) Set up position / scaling / rotation, etc

string str = "12";
float strLength = glutStrokeLength(GLUT_STROKE_ROMAN, (const unsigned char*)str.c_str() );
float strScale = 0.3;

glPushMatrix();
glLineWidth(2.0);
glTranslatef( -strLength * strScale / 2, 0.0, 0.0 );
glScalef(strScale, strScale, strScale);
glColor3ub(255, 0, 0);
renderStrokeString( GLUT_STROKE_ROMAN, str );
glPopMatrix();

That’s it!