#include <u.h>#include <libc.h>#include <stdio.h>#include "../dat.h"#include "../fns.h"  /*============================================================================== PLAYER TRAIL ============================================================================== This is a circular list containing the a list of points of wherethe player has been recently.  It is used by monsters for pursuit. .origin		the spot.owner		forward link.aiment		backward link*/  #define	TRAIL_LENGTH	8 edict_t		*trail[TRAIL_LENGTH];int			trail_head;qboolean	trail_active = false; #define NEXT(n)		(((n) + 1) & (TRAIL_LENGTH - 1))#define PREV(n)		(((n) - 1) & (TRAIL_LENGTH - 1))  void PlayerTrail_Init (void){	int		n; 	if (deathmatch->value /* FIXME || coop */)		return; 	for (n = 0; n < TRAIL_LENGTH; n++)	{		trail[n] = G_Spawn();		trail[n]->classname = "player_trail";	} 	trail_head = 0;	trail_active = true;}  void PlayerTrail_Add (vec3_t spot){	vec3_t	temp; 	if (!trail_active)		return; 	VectorCopy (spot, trail[trail_head]->s.origin); 	trail[trail_head]->timestamp = level.time; 	VectorSubtract (spot, trail[PREV(trail_head)]->s.origin, temp);	trail[trail_head]->s.angles[1] = vectoyaw (temp); 	trail_head = NEXT(trail_head);}  void PlayerTrail_New (vec3_t spot){	if (!trail_active)		return; 	PlayerTrail_Init ();	PlayerTrail_Add (spot);}  edict_t *PlayerTrail_PickFirst (edict_t *self){	int		marker;	int		n; 	if (!trail_active)		return NULL; 	for (marker = trail_head, n = TRAIL_LENGTH; n; n--)	{		if(trail[marker]->timestamp <= self->monsterinfo.trail_time)			marker = NEXT(marker);		else			break;	} 	if (visible(self, trail[marker]))	{		return trail[marker];	} 	if (visible(self, trail[PREV(marker)]))	{		return trail[PREV(marker)];	} 	return trail[marker];} edict_t *PlayerTrail_PickNext (edict_t *self){	int		marker;	int		n; 	if (!trail_active)		return NULL; 	for (marker = trail_head, n = TRAIL_LENGTH; n; n--)	{		if(trail[marker]->timestamp <= self->monsterinfo.trail_time)			marker = NEXT(marker);		else			break;	} 	return trail[marker];} edict_t *PlayerTrail_LastSpot (void){	return trail[PREV(trail_head)];}