FTGL demo样例

针对下面不同的风格：

    fonts[0] = new FTGLOutlineFont(fontfile);
    fonts[1] = new FTGLPolygonFont(fontfile);
    fonts[2] = new FTGLTextureFont(fontfile);
    fonts[3] = new FTGLBitmapFont(fontfile);
    fonts[4] = new FTGLPixmapFont(fontfile);

渲染字体效果：

//#include // exit()
//
//#include
//#include

#include "config.h"

#include
#include

#if defined HAVE_GL_GLUT_H
#   include
#elif defined HAVE_GLUT_GLUT_H
#   include
#else
#   error GLUT headers not present
#endif

#include "FTGL/FTGLOutlineFont.h"
#include "FTGL/FTGLPolygonFont.h"
#include "FTGL/FTGLBitmapFont.h"
#include "FTGL/FTGLTextureFont.h"
#include "FTGL/FTGLPixmapFont.h"

static FTFont* fonts[5];
static int width;
static int height;
using namespace std;

void
my_init( const char* font_filename )
{
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 char *fontfile="c:\\windows\\fonts\\simhei.ttf";
    fonts[0] = new FTGLOutlineFont(fontfile);
    fonts[1] = new FTGLPolygonFont(fontfile);
    fonts[2] = new FTGLTextureFont(fontfile);
    fonts[3] = new FTGLBitmapFont(fontfile);
    fonts[4] = new FTGLPixmapFont(fontfile);
    for (int i=0; i< 5; i++) {
        if (fonts[i]->Error()) {
            cerr << "ERROR: Unable to open file " << font_filename << "\n";
        }
        else {
            int point_size = 12;
            if (!fonts[i]->FaceSize(point_size)) {
                cerr << "ERROR: Unable to set font face size " << point_size << "\n";
            }
        }
    }
}

static void do_ortho()
{
  int w;
  int h;
  GLdouble size;
  GLdouble aspect;

  w = width;
  h = height;
  aspect = (GLdouble)w / (GLdouble)h;

  // Use the whole window.
  glViewport(0, 0, w, h);

  // We are going to do some 2-D orthographic drawing.
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  size = (GLdouble)((w >= h) ? w : h) / 2.0;
  if (w <= h) {
    aspect = (GLdouble)h/(GLdouble)w;
    glOrtho(-size, size, -size*aspect, size*aspect,
            -100000.0, 100000.0);
  }
  else {
    aspect = (GLdouble)w/(GLdouble)h;
    glOrtho(-size*aspect, size*aspect, -size, size,
            -100000.0, 100000.0);
  }

  // Make the world and window coordinates coincide so that 1.0 in
  // model space equals one pixel in window space.
  glScaled(aspect, aspect, 1.0);

   // Now determine where to draw things.
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
}

void my_reshape(int w, int h)
{
  width = w;
  height = h;
}

void my_handle_key(unsigned char key, int x, int y)
{
   switch (key) {

   case 27:    // Esc - Quits the program.
       for (int i=0; i<5; i++) {
           if (fonts[i]) {
               delete fonts[i];
               fonts[i] = 0;
           }
       }
      exit(1);
      break;

   default:
      break;
   }
}

void draw_scene()
{
   /* Set up some strings with the characters to draw. */
   unsigned int count = 0;
   char string[8][256];
   int i;
   for (i=1; i < 32; i++) { /* Skip zero - it's the null terminator! */
      string[0][count] = i;
      count++;
   }
   string[0][count] = '\0';

   count = 0;
   for (i=32; i < 64; i++) {
      string[1][count] = i;
      count++;
   }
   string[1][count] = '\0';

   count = 0;
   for (i=64; i < 96; i++) {
      string[2][count] = i;
      count++;
   }
   string[2][count] = '\0';

   count = 0;
   for (i=96; i < 128; i++) {
      string[3][count] = i;
      count++;
   }
   string[3][count] = '\0';

   count = 0;
   for (i=128; i < 160; i++) {
      string[4][count] = i;
      count++;
   }
   string[4][count] = '\0';

   count = 0;
   for (i=160; i < 192; i++) {
      string[5][count] = i;
      count++;
   }
   string[5][count] = '\0';

   count = 0;
   for (i=192; i < 224; i++) {
      string[6][count] = i;
      count++;
   }
   string[6][count] = '\0';

   count = 0;
   for (i=224; i < 256; i++) {
      string[7][count] = i;
      count++;
   }
   string[7][count] = '\0';

   glColor3f(1.0, 1.0, 1.0);

   for (int font = 0; font < 5; font++) {
       GLfloat x = -250.0;
       GLfloat y;
       GLfloat yild = 20.0;
       for (int j=0; j<4; j++) {
           y = 275.0-font*120.0-j*yild;
           if (font >= 3) {
               glRasterPos2f(x, y);
               fonts[font]->Render(string[j]);
           }
           else {
               if (font == 2) {
                   glEnable(GL_TEXTURE_2D);
                   glEnable(GL_BLEND);
                   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
               }
               glPushMatrix(); {
                   glTranslatef(x, y, 0.0);
                   fonts[font]->Render(string[j]);
               } glPopMatrix();
               if (font == 2) {
                   glDisable(GL_TEXTURE_2D);
                   glDisable(GL_BLEND);
               }
           }
       }
   }
}

void my_display(void)
{
    glClear(GL_COLOR_BUFFER_BIT);

    do_ortho();

    draw_scene();

    glutSwapBuffers();
}

int main(int argc, char **argv)
{

   glutInitWindowSize(600, 600);
   glutInit(&argc, argv);
   glutInitDisplayMode(GLUT_RGB|GLUT_DOUBLE);

   glutCreateWindow("FTGL demo");

   int result = 1;
   if ( argc != 2 ) {
       //cerr << "usage: " << argv[0] << " font_filename.ttf\n";
       result = 0;
   }
   else {
       my_init(argv[1]);

       glutDisplayFunc(my_display);
       glutReshapeFunc(my_reshape);
       glutKeyboardFunc(my_handle_key);

       glutMainLoop();
   }
   exit(result);
}