Global Save File / Persistent Variables for RPG Maker VXA

#~ Dumps certain variables into a global save file. In order to them to be
#~ dumped, tag their name (the name in the editor) with an * (asterisk).

#~ ~Kread

GLOBAL_SAVEFILE_NAME = 'Global_Data.rvdata2'

#==============================================================================
# ** DataManager
#==============================================================================

module DataManager
  #--------------------------------------------------------------------------
  # * Create the game objects
  #--------------------------------------------------------------------------
  class << self; alias_method(:krx_gsf_dl_cgo, :create_game_objects); end
  def self.create_game_objects
    krx_gsf_dl_cgo
    $game_system.read_global_savefile(GLOBAL_SAVEFILE_NAME)
  end
end

#==============================================================================
# ** Game_System
#==============================================================================

class Game_System
  #--------------------------------------------------------------------------
  # * Write the global savefile
  #--------------------------------------------------------------------------
  def write_global_savefile(filename)
    contents = []
    (1..$game_variables.size).each do |i|
      next unless $data_system.variables[i].include?('*')
      contents.push([i, $game_variables[i]])
    end
    File.open(filename, 'wb') do |file|
      Marshal.dump(contents, file)
    end
    true
  end
  #--------------------------------------------------------------------------
  # * Read the global savefile
  #--------------------------------------------------------------------------
  def read_global_savefile(filename)
    contents = nil
    if FileTest.exist?(filename)
      File.open(filename, 'rb') {|file| contents = Marshal.load(file)}
    end
    return false unless contents
    contents.each {|array| $game_variables[array[0]] = array[1]}
    true
  end
end

#==============================================================================
# ** Game_Variables
#==============================================================================

class Game_Variables
  #--------------------------------------------------------------------------
  # * Returns the data size
  #--------------------------------------------------------------------------
  def size
    @data.size
  end
  #--------------------------------------------------------------------------
  # * Assigns a value
  #--------------------------------------------------------------------------
  alias_method(:krx_gsf_gv_ass, :[]=)
  def []=(variable_id, value)
    krx_gsf_gv_ass(variable_id, value)
    if $data_system.variables[variable_id].include?('*')
      $game_system.write_global_savefile(GLOBAL_SAVEFILE_NAME)
    end
  end
end