memset(imagedata, 0, tex_side * tex_side * 4);//清零
for( i = startglyph, l = 0, m = 0, n = 0; i < endglyph; i++ )//遍历每个字,
{
ft_error ftresult;
// load & render glyph
ftresult = ft_load_char( mttfmsg->face, i, ft_load_render );//读取字体