HACKING

/*
 *    Copyright (C) 1987, 1988 Chuck Simmons
 * 
 * See the file COPYING, distributed with empire, for restriction
 * and warranty information.
 */

C Empire Sources (now called vms-empire).

A few notes on how to debug and modify this code.  This used to be
part of the README.

Organization:

        empire.h   -- definitions of data structures
        extern.h   -- definitions of global variables
        data.c     -- constant data
	main.c     -- option parsing
        empire.c   -- main program loop and outermost command handler
        usermove.c -- move the user's pieces
        compmove.c -- move the computer's pieces
        edit.c     -- handle the user's edit mode commands
        game.c     -- saving, restoring, and initializing the game board
        display.c  -- update the screen
	term.c     -- deal with information area of screen
        math.c     -- mathematical routines
        object.c   -- routines for manipulating objects
	attack.c   -- handle attacks between pieces
	map.c      -- find paths for moving pieces
	util.c     -- miscellaneous routines, especially I/O.

Debugging notes:

	From command mode, there are two special commands that
	can be used to turn debugging mode on or off.  "++" turns
	debugging mode on.  "+-" turns debugging mode off.

	When debugging mode is turned on, the following commands are
	available:

	"#" -- display a sector of the computer's map.

	"%" -- enter "movie" mode.  The computer continuously makes
	       moves, and the computer's map is shown on the screen.
	       This is useful for debugging the algorithm used by the
	       computer when it makes a move.  Don't confuse this
	       with saving a movie and replaying it.

	"@" -- enable/disable "trace pathmap" mode.  If this command
	       is followed by a "+", trace pathmap mode is enabled.
	       If this command is followed by a "-", trace pathmap
	       mode is disabled.  In this mode, every time a "pathmap"
	       is created, it is displayed.  This is useful for
	       debugging the subroutines that search for an optimal
	       path along which to move a piece.

	"$" -- enable/disable "print_debug".  This command is also
	       followed by either a "+" or "-".  In this mode,
	       various messages will be printed out at times which
	       may indicate that something is being done non-optimally.

	"&" -- enable/disable "print_vmap".  This command is followed
	       by a char that specifies the type of vmap to be
	       displayed.  Values are

		"a" -- army load maps
		"l" -- transport load maps
		"u" -- transport unload maps
		"s" -- ship maps
		"i" -- pruned explore map

	       Any other character disables the printing of vmaps.

	The program will not provide any prompts for the debugging
	commands.  If you make a mistake, the computer just beeps.

	You can also replay a saved movie with the normal "W" command
	when debugging mode is turned on.

	Also, the -DDEBUG flag can be turned on to cause consistency
	checking to be performed frequently on the internal database.
	This consistency checking is fairly exhaustive and checks for
	all sorts of screwed up pointers.  My measurements suggest
	that consistency checking causes the program to run half
	as fast.