From B. (Bernd.Kreimeier@nero.uni-bonn.de), 1995


I got this info about the Netgame packet structure from Jake Page.
It has been posted by Antony Suter <antony@werple.apana.org.au>
on a.g.d. in 1994, who got it from Id.

Remember, Objective C.


/*  Note that type unsigned is a 4 byte quantity */


typedef struct
{
	char		forwardmove;	  // *2048 for move
	char		sidemove;	  // *2048 for move
	short		angleturn;	  // <<16 for angle delta
	short		consistancy;	  // checks for net game
	byte		chatchar;
	byte		buttons;
} ticcmd_t;

#define	BT_ATTACK		1
#define	BT_USE			2
#define	BT_CHANGE		4   // if true, 
                                    // the next 3 bits hold weapon num
#define	BT_WEAPONMASK	(8+16+32)
#define	BT_WEAPONSHIFT	3

#define BT_SPECIAL	      128   // game events, not really buttons
#define	BTS_SAVEMASK	(4+8+16)
#define	BTS_SAVESHIFT	2
#define	BT_SPECIALMASK	3
#define	BTS_PAUSE		1   // pause the game
#define	BTS_SAVEGAME	2	    // save the game at each console
// savegame slot numbers occupy the second byte of buttons

typedef struct
{
	unsigned	checksum;	// high bit is retransmit request
	byte		retransmitfrom;	// only valid if NCMD_RETRANSMIT
	byte		starttic;
	byte		player, numtics;		
	ticcmd_t	cmds[BACKUPTICS];
} doomdata_t;

int	NetbufferSize (void)
{
	return (int)&( ((doomdata_t *)0)->cmds[netbuffer->numtics] ); 

}

unsigned NetbufferChecksum (void)
{
	unsigned		c;
	int		i,l;

	c = 0x1234567;

#ifdef NeXT
	return 0;			// byte order problems
#endif

	l = (NetbufferSize () 
                 - (int)&(((doomdata_t*)0)->retransmitfrom))/4;
	for (i=0 ; i<l ; i++)
	  c += ((unsigned *)&netbuffer->retransmitfrom)[i] * (i+1);

	return c & NCMD_CHECKSUM;
}