Trouble with font glyphs for control characters

I've been meaning to add glyphys to the actual control characters for my project's font. I used a hexadecimal editor extension of Visual Studio Code to manually insert the bytes in the FNT file. It actually worked for most characters, with the exception of:

  • 0x00, null
  • 0x09, horizontal tab
  • 0x0A, line feed
  • 0x0D, carriage return

For now, these characters have been replaced with their Unicode control picture counterparts in my font file. From what I've looked at in the documentation, the space character is the only one that gets a reserved word, rather than the byte itself.

What can be done to apply these glyphs to the remaining control bytes? Is there a smarter workaround to it?

You can use U+xxxx for any codepoint in the first two Unicode planes.