Function load_font

leif.c:1068–1131

}

LfFont load_font(const char* filepath, uint32_t pixelsize, uint32_t tex_width, uint32_t tex_height,  uint32_t line_gap_add) {
  LfFont font = {0};
  /* Opening the file, reading the content to a buffer and parsing the loaded data with stb_truetype */
  FILE* file = fopen(filepath, "rb");
  if (file == NULL) {
    LF_ERROR("Failed to open font file '%s'\n", filepath);
  }

  // Loading the content
  fseek(file, 0, SEEK_END);
  long fileSize = ftell(file);
  fseek(file, 0, SEEK_SET);
  uint8_t* buffer = (uint8_t*)malloc(fileSize);
  size_t bytesRead = fread(buffer, 1, fileSize, file);
  fclose(file); 
  if (bytesRead != fileSize) {
    LF_ERROR("Failed to read font file '%s'\n", filepath);
    // Handle the error (e.g., free memory and return from the function)
    free(buffer);
    LfFont emptyFont = {0}; // Or whatever initialization you need
    return emptyFont;
}
  font.font_info = malloc(sizeof(stbtt_fontinfo));

  // Initializing the font with stb_truetype
  stbtt_InitFont((stbtt_fontinfo*)font.font_info, buffer, stbtt_GetFontOffsetForIndex(buffer, 0));

  stbtt_fontinfo* fontinfo = (stbtt_fontinfo*)font.font_info;
  int numglyphs = fontinfo->numGlyphs;

  // Loading the font bitmap to memory by using stbtt_BakeFontBitmap
  uint8_t* bitmap = (uint8_t*)malloc(tex_width * tex_height * sizeof(uint32_t));
  uint8_t* bitmap_4bpp = (uint8_t*)malloc(tex_width * tex_height * 4 * sizeof(uint32_t));
  font.cdata = malloc(sizeof(stbtt_bakedchar) * numglyphs);
  font.tex_width = tex_width;
  font.tex_height = tex_height;
  font.line_gap_add = line_gap_add;
  font.font_size = pixelsize;
  font.num_glyphs = numglyphs;
  stbtt_BakeFontBitmap(buffer, 0, pixelsize, bitmap, tex_width, tex_height, 32, numglyphs, (stbtt_bakedchar*)font.cdata);

  uint32_t bitmap_index = 0;
  for(uint32_t i = 0; i < (uint32_t)(tex_width * tex_height * 4); i++) {
    bitmap_4bpp[i] = bitmap[bitmap_index];
    if((i + 1) % 4 == 0) {
      bitmap_index++;
    }
  }

  // Creating an opengl texture (texture atlas) for the font
  glGenTextures(1, &font.bitmap.id);
  glBindTexture(GL_TEXTURE_2D, font.bitmap.id);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_LINEAR);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, tex_width, tex_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, bitmap_4bpp);
  glGenerateMipmap(GL_TEXTURE_2D);