lovr/src/loaders/font.c

#include "loaders/font.h"
#include "util.h"
#include <ft2build.h>
#include FT_FREETYPE_H
#include FT_GLYPH_H

static FT_Library ft = NULL;

FontData* lovrFontDataCreate(void* data, int size, int height) {
  if (!ft && FT_Init_FreeType(&ft)) {
    error("Error initializing FreeType");
  }

  FontData* fontData = malloc(sizeof(FontData));
  fontData->size = height;

  FT_Error err = FT_Err_Ok;
  err = err || FT_New_Memory_Face(ft, data, size, 0, (FT_Face*)&fontData->rasterizer);
  err = err || FT_Set_Pixel_Sizes(fontData->rasterizer, 0, height);

  if (err) {
    error("Problem loading font\n");
  }

  return fontData;
}

void lovrFontDataDestroy(FontData* fontData) {
  FT_Done_Face(fontData->rasterizer);
  free(fontData);
}

void lovrFontDataLoadGlyph(FontData* fontData, uint32_t character, Glyph* glyph) {
  FT_Face face = fontData->rasterizer;
  FT_Error err = FT_Err_Ok;
  FT_Glyph slot;
  FT_Bitmap bitmap;
  FT_BitmapGlyph bmglyph;
  FT_Glyph_Metrics* metrics;

  // FreeType stuff
  err = err || FT_Load_Glyph(face, FT_Get_Char_Index(face, character), FT_LOAD_DEFAULT);
  err = err || FT_Get_Glyph(face->glyph, &slot);
  err = err || FT_Glyph_To_Bitmap(&slot, FT_RENDER_MODE_NORMAL, 0, 1);

  if (err) {
    error("Error loading glyph\n");
  }

  bmglyph = (FT_BitmapGlyph) slot;
  bitmap = bmglyph->bitmap;
  metrics = &face->glyph->metrics;

  // Initialize glyph
  glyph->x = 0;
  glyph->y = 0;
  glyph->w = metrics->width >> 6;
  glyph->h = metrics->height >> 6;
  glyph->dx = metrics->horiBearingX >> 6;
  glyph->dy = metrics->horiBearingY >> 6;
  glyph->advance = metrics->horiAdvance >> 6;
  glyph->data = malloc(glyph->w * glyph->h * 2 * sizeof(uint8_t));

  // Transform data into an OpenGL-friendly format
  int i = 0;
  uint8_t* row = bitmap.buffer;
  for (int y = 0; y < glyph->h; y++) {
    for (int x = 0; x < glyph->w; x++) {
      glyph->data[i++] = 0xff;
      glyph->data[i++] = row[x];
    }
    row += bitmap.pitch;
  }

  FT_Done_Glyph(slot);
}