// bitmap font draw sample on OpenGL
//
// Last updated: <2024/01/13 09:32:22 +0900>

#include <windows.h>
#include <stdio.h>
#include <string.h>
#include <GL/gl.h>
#include <GL/freeglut.h>

// include bitmap pattern
// --------------------
// #include "fontdata.h"
// #include "fontdata_courr18.h"
// #include "fontdata_shnm8x16r.h"
// #include "fontdata_shnm8x16rx2.h"
// #include "fontdata_profont.h"
#include "fontdata_ter-u24b.h"

#define SCRW 512
#define SCRH 288

static int framerate = 60;

static int count = 0;

// draw text
void drawText(char *str)
{
  GLsizei w = (GLsizei)fontdata_width;
  GLsizei h = (GLsizei)fontdata_height;
  int clen = fontdata_chr_len;
  GLfloat xorig, yorig;
  GLfloat xmove, ymove;
  xorig = 0;
  yorig = 0;
  xmove = w;
  ymove = 0;

  glPixelStorei(GL_UNPACK_ALIGNMENT, 1); // コレが無いと表示が崩れる

  int slen = strlen(str);
  for (int i = 0; i < slen; i++)
  {
    int c = str[i];
    if (c == 0)
      break;
    if (c < 0x20 || c > 0x7f)
      c = 0x20;
    c -= 0x20;
    glBitmap(w, h, xorig, yorig, xmove, ymove, &(fontdata[c][0]));
  }
}

// draw OpenGL
void display(void)
{
  GLfloat xorig, yorig, xmove, ymove;
  GLsizei w, h;

  glClearColor(0.0, 0.0, 0.0, 0.0);
  glClear(GL_COLOR_BUFFER_BIT);

  // draw text
  glColor4f(1, 1, 1, 1);    // set color
  glRasterPos2f(-0.8, 0.5); // set position
  drawText("Hello World !!");

  {
    char buf[256];
    sprintf(buf, "count %d", count);
    glRasterPos2f(-0.8, 0.0);
    drawText(buf);
  }

  glutSwapBuffers();
  glFlush();

  count++;
}

void onTimer(int value)
{
  glutPostRedisplay(); // redraw
  glutTimerFunc((1000 / framerate), onTimer, 0);
}

void keyboard(unsigned char key, int x, int y)
{
  switch (key)
  {
  case '\x1B':
  case 'q':
    // Exit on escape or 'q' key press
    glutLeaveMainLoop();
    // exit(EXIT_SUCCESS);
    break;
  }
}

int main(int argc, char **argv)
{
  count = 0;
  
  glutInit(&argc, argv);
  glutInitWindowSize(SCRW, SCRH);
  glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH);

  glutCreateWindow("bitmap font draw sample");
  glutKeyboardFunc(keyboard);
  glutDisplayFunc(display);

  glutTimerFunc((1000 / framerate), onTimer, 0);

  glutMainLoop();
  return EXIT_SUCCESS;
}