Re: Writing into gtkglarea

[Paolo Costabel <paolo futurecombat net>]

Sven Kobow wrote:

> Hello,
>
> does anybody know how i can simply write into a gtkglarea? Is there something 
> real simple? like printf or puts? 
>
> Thanx a lot
>
> Sven
> _______________________________________________
> gtk-app-devel-list mailing list
> gtk-app-devel-list gnome org
> http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
I have attached a file that implements a simple printString function for 
OpenGL.
You need to create the font first by calling makeRasterFont().

/*
 *  font.c
 *
 *  Draws text in a bitmapped font. 
 */
#include <GL/glut.h>
#include <stdlib.h>
#include <string.h>

GLubyte space[] = 
{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};

GLubyte letters[][13] = {
{0x00, 0x00, 0xc3, 0xc3, 0xc3, 0xc3, 0xff, 0xc3, 0xc3, 0xc3, 0x66, 0x3c, 0x18}, 
{0x00, 0x00, 0xfe, 0xc7, 0xc3, 0xc3, 0xc7, 0xfe, 0xc7, 0xc3, 0xc3, 0xc7, 0xfe}, 
{0x00, 0x00, 0x7e, 0xe7, 0xc0, 0xc0, 0xc0, 0xc0, 0xc0, 0xc0, 0xc0, 0xe7, 0x7e}, 
{0x00, 0x00, 0xfc, 0xce, 0xc7, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0xc7, 0xce, 0xfc}, 
{0x00, 0x00, 0xff, 0xc0, 0xc0, 0xc0, 0xc0, 0xfc, 0xc0, 0xc0, 0xc0, 0xc0, 0xff}, 
{0x00, 0x00, 0xc0, 0xc0, 0xc0, 0xc0, 0xc0, 0xc0, 0xfc, 0xc0, 0xc0, 0xc0, 0xff}, 
{0x00, 0x00, 0x7e, 0xe7, 0xc3, 0xc3, 0xcf, 0xc0, 0xc0, 0xc0, 0xc0, 0xe7, 0x7e}, 
{0x00, 0x00, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0xff, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3}, 
{0x00, 0x00, 0x7e, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0x7e}, 
{0x00, 0x00, 0x7c, 0xee, 0xc6, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06}, 
{0x00, 0x00, 0xc3, 0xc6, 0xcc, 0xd8, 0xf0, 0xe0, 0xf0, 0xd8, 0xcc, 0xc6, 0xc3}, 
{0x00, 0x00, 0xff, 0xc0, 0xc0, 0xc0, 0xc0, 0xc0, 0xc0, 0xc0, 0xc0, 0xc0, 0xc0}, 
{0x00, 0x00, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0xdb, 0xff, 0xff, 0xe7, 0xc3}, 
{0x00, 0x00, 0xc7, 0xc7, 0xcf, 0xcf, 0xdf, 0xdb, 0xfb, 0xf3, 0xf3, 0xe3, 0xe3}, 
{0x00, 0x00, 0x7e, 0xe7, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0xe7, 0x7e}, 
{0x00, 0x00, 0xc0, 0xc0, 0xc0, 0xc0, 0xc0, 0xfe, 0xc7, 0xc3, 0xc3, 0xc7, 0xfe}, 
{0x00, 0x00, 0x3f, 0x6e, 0xdf, 0xdb, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0x66, 0x3c}, 
{0x00, 0x00, 0xc3, 0xc6, 0xcc, 0xd8, 0xf0, 0xfe, 0xc7, 0xc3, 0xc3, 0xc7, 0xfe}, 
{0x00, 0x00, 0x7e, 0xe7, 0x03, 0x03, 0x07, 0x7e, 0xe0, 0xc0, 0xc0, 0xe7, 0x7e}, 
{0x00, 0x00, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0xff}, 
{0x00, 0x00, 0x7e, 0xe7, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3}, 
{0x00, 0x00, 0x18, 0x3c, 0x3c, 0x66, 0x66, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3}, 
{0x00, 0x00, 0xc3, 0xe7, 0xff, 0xff, 0xdb, 0xdb, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3}, 
{0x00, 0x00, 0xc3, 0x66, 0x66, 0x3c, 0x3c, 0x18, 0x3c, 0x3c, 0x66, 0x66, 0xc3}, 
{0x00, 0x00, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0x3c, 0x3c, 0x66, 0x66, 0xc3}, 
{0x00, 0x00, 0xff, 0xc0, 0xc0, 0x60, 0x30, 0x7e, 0x0c, 0x06, 0x03, 0x03, 0xff}
};

GLubyte numbers[][13] = {
{0x00, 0x00, 0x7e, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0xc3, 0x7e}, 
{0x00, 0x00, 0x7e, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0xf8, 0x78, 0x18}, 
{0x00, 0x00, 0xff, 0xc0, 0xc0, 0x60, 0x30, 0x18, 0x0c, 0x06, 0x03, 0x83, 0x7e},
{0x00, 0x00, 0xfe, 0x03, 0x03, 0x03, 0x03, 0xfe, 0x03, 0x03, 0x03, 0x03, 0xfe}, 
{0x00, 0x00, 0x03, 0x03, 0x03, 0xff, 0xc0, 0xc0, 0x60, 0x30, 0x18, 0x0c, 0x06}, 
{0x00, 0x00, 0xfe, 0x03, 0x03, 0x03, 0x03, 0xfe, 0xc0, 0xc0, 0xc0, 0xc0, 0xff}, 
{0x00, 0x00, 0x7e, 0xc3, 0xc3, 0xc3, 0xc3, 0xfe, 0xc0, 0xc0, 0xc0, 0xc1, 0x7e}, 
{0x00, 0x00, 0x60, 0x60, 0x60, 0x30, 0x18, 0x0c, 0x06, 0x03, 0x03, 0x03, 0xff},
{0x00, 0x00, 0x7e, 0xc3, 0xc3, 0xc3, 0xc3, 0x7e, 0xc3, 0xc3, 0xc3, 0xc3, 0x7e}, 
{0x00, 0x00, 0x7e, 0xc3, 0x03, 0x03, 0x03, 0x7f, 0xc3, 0xc3, 0xc3, 0xc3, 0x7e}
};

GLuint fontOffset=-1;

void makeRasterFont(void)
{
   GLuint i, j;
   glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

   fontOffset = glGenLists (128);
   for (i = 0,j = 'A'; i < 26; i++,j++) {
      glNewList(fontOffset + j, GL_COMPILE);
      glBitmap(8, 13, 0.0, 2.0, 10.0, 0.0, letters[i]);
      glEndList();
   }
   for (i = 0,j = '0'; i < 10; i++,j++) {
      glNewList(fontOffset + j, GL_COMPILE);
      glBitmap(8, 13, 0.0, 2.0, 10.0, 0.0, numbers[i]);
      glEndList();
   }
   glNewList(fontOffset + ' ', GL_COMPILE);
   glBitmap(8, 13, 0.0, 2.0, 10.0, 0.0, space);
   glEndList();
}

void
freeRasterFont()
{
   if(fontOffset!=-1)
        glDeleteLists(fontOffset,128);
}

void printString(char *s)
{
   if(fontOffset==-1)
                makeRasterFont();
   glPushAttrib (GL_LIST_BIT);
   glListBase(fontOffset);
   glCallLists((GLsizei) strlen(s), GL_UNSIGNED_BYTE, (GLubyte *) s);
   glPopAttrib ();
}