# Permission is granted to use, modify and distribute
# this code freely, provided that this license clause
# remains intact.

# This code is intended to convert AngelCode BMFont font files
# (.fnt) into a header file, for use with Nintendo DS homebrew
# development. 

# This is intended to be used with the object files created by bin2o
# in devkitPro. If the font name has spaces in it, this will probably break.
# Try using underscores instead.

# Another feature provided is that the kerning nodes are sorted to allow
# binary search of kerning nodes, if you don't want to go to the effort of
# putting them in a proper data structure.

# An example declaration of the FontInfo, CharInfo, and KerningInfo structures 
# expected by this code:

%{
  namespace demo {
    struct FontInfo {
      const char* name; //Font name
      uint16 size;      //Font 'size'
      uint16 height;    //Actual line height of the font (may be different from size)
      bool bold, italic;
      Rect padding;
      Rect rectangle;   //Area of the image file containing font data (usually {0,0, width,height})
      const u8* data;   //Pointer to the data (format not specified)
      uint32 dataSize;  //Size of data
      uint16 charCount;    //Number of characters
      uint32 kerningCount; //Number of kerning nodes
    };

    struct CharInfo {
      uint16 id;  //Code point
      uint16 x, y; //Position of the glyph in the bitmap
      uint8 width, height; //Size of the glyph
      int8 xoffset, yoffset; //How much to offset the glyph on the screen
      uint8 xadvance; 
      uint8 page; //If there are several bitmaps, this is useful. I usually avoid this.
    } PACKED;

    struct KerningInfo {
      uint16 first, second;
      signed char kerning;
    } PACKED;
  }
}

for file in ARGV
  lines = File.open(file, "r") do |f|
    f.read
  end
  
  face = nil
  size = nil
  width = nil
  height = nil
  line_height = nil
  
  chars = []
  kerning = []
  
  # This could be better, but it works...
  for line in lines
    m = /(\w+)\s+(.*)/.match(line)
    if m
      name = m[1]
      parts = {}
      
      m[2].split(/\s+/).each do |ma|
        ma=ma.split('=')
        parts[ma[0]] = ma[1]
      end
      
      case name
        when "info"
          face = parts["face"].gsub(/(^\")|(\"$)/,'');
          size = parts["size"].to_i
          bold = parts["bold"].to_i
          italic = parts["italic"].to_i
        when "common"
          line_height = parts["lineHeight"].to_i
          width = parts["scaleW"].to_i
          height = parts["scaleH"].to_i
        when "char"
          char = []
          char << parts["id"] << parts["x"] << parts["y"] << parts["width"] << parts["height"] << parts["xoffset"] << parts["yoffset"] << parts["xadvance"] << parts["page"]
          chars << char
        when "kerning"
          kern = []
          kern << parts["first"] << parts["second"] << parts["amount"]
          kerning << kern
        else
      end
    end
  end
  
  #Sort the kernings by first, then second.
  kerning = kerning.map {|k|
    k.map{|ki|
      ki.to_i
    }
  }
  
  kerning.sort! do |a,b|
    if a[0] != b[0]
      a[0] <=> b[0]
    elsif a[1] != b[1]
      a[1] <=> b[1]
    else
      0
    end
  end
  
  # Obviously, modify this part to suit your needs.
  # I should probably put the padding value in there too...
  File.open(file.gsub(/\.fnt$/,'.h'), "w") do |fh|
    fh.puts <<HEADER
#include "types.h"
#include "font.h"
#include "#{face}_#{size}_bin.h"

namespace demo {
	FontInfo #{face}#{size} = {
	  "#{face}", #{size}, #{line_height}, #{bold}, #{italic},
	  Rect(0,0,0,0),
	  Rect(0,0,#{width},#{height}),
	  #{face}_#{size}_bin, #{face}_#{size}_bin_size
	};
  
  CharInfo #{face}_#{size}_Chars[#{chars.length}] = {
HEADER

    for char in chars
      fh.puts "    { #{char.join(", ")} },"
    end
  
    # End of the characters, start of the kerning nodes.
    fh.puts <<MIDDLE
  };
  
  KerningInfo #{face}_#{size}_Kerning[#{kerning.length}] = {
MIDDLE

    for kern in kerning
      fh.puts "    { #{kern.join(", ") } },"
    end
  
    #End of the file.
    fh.puts <<END
  
  };
}
END
  end
end