Quake-2

Quake 2 GPL Source Release
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p_trail.c (2852B)

      1 /*
      2 Copyright (C) 1997-2001 Id Software, Inc.
      3 
      4 This program is free software; you can redistribute it and/or
      5 modify it under the terms of the GNU General Public License
      6 as published by the Free Software Foundation; either version 2
      7 of the License, or (at your option) any later version.
      8 
      9 This program is distributed in the hope that it will be useful,
     10 but WITHOUT ANY WARRANTY; without even the implied warranty of
     11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  
     12 
     13 See the GNU General Public License for more details.
     14 
     15 You should have received a copy of the GNU General Public License
     16 along with this program; if not, write to the Free Software
     17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
     18 
     19 */
     20 #include "g_local.h"
     21 
     22 
     23 /*
     24 ==============================================================================
     25 
     26 PLAYER TRAIL
     27 
     28 ==============================================================================
     29 
     30 This is a circular list containing the a list of points of where
     31 the player has been recently.  It is used by monsters for pursuit.
     32 
     33 .origin		the spot
     34 .owner		forward link
     35 .aiment		backward link
     36 */
     37 
     38 
     39 #define	TRAIL_LENGTH	8
     40 
     41 edict_t		*trail[TRAIL_LENGTH];
     42 int			trail_head;
     43 qboolean	trail_active = false;
     44 
     45 #define NEXT(n)		(((n) + 1) & (TRAIL_LENGTH - 1))
     46 #define PREV(n)		(((n) - 1) & (TRAIL_LENGTH - 1))
     47 
     48 
     49 void PlayerTrail_Init (void)
     50 {
     51 	int		n;
     52 
     53 	if (deathmatch->value /* FIXME || coop */)
     54 		return;
     55 
     56 	for (n = 0; n < TRAIL_LENGTH; n++)
     57 	{
     58 		trail[n] = G_Spawn();
     59 		trail[n]->classname = "player_trail";
     60 	}
     61 
     62 	trail_head = 0;
     63 	trail_active = true;
     64 }
     65 
     66 
     67 void PlayerTrail_Add (vec3_t spot)
     68 {
     69 	vec3_t	temp;
     70 
     71 	if (!trail_active)
     72 		return;
     73 
     74 	VectorCopy (spot, trail[trail_head]->s.origin);
     75 
     76 	trail[trail_head]->timestamp = level.time;
     77 
     78 	VectorSubtract (spot, trail[PREV(trail_head)]->s.origin, temp);
     79 	trail[trail_head]->s.angles[1] = vectoyaw (temp);
     80 
     81 	trail_head = NEXT(trail_head);
     82 }
     83 
     84 
     85 void PlayerTrail_New (vec3_t spot)
     86 {
     87 	if (!trail_active)
     88 		return;
     89 
     90 	PlayerTrail_Init ();
     91 	PlayerTrail_Add (spot);
     92 }
     93 
     94 
     95 edict_t *PlayerTrail_PickFirst (edict_t *self)
     96 {
     97 	int		marker;
     98 	int		n;
     99 
    100 	if (!trail_active)
    101 		return NULL;
    102 
    103 	for (marker = trail_head, n = TRAIL_LENGTH; n; n--)
    104 	{
    105 		if(trail[marker]->timestamp <= self->monsterinfo.trail_time)
    106 			marker = NEXT(marker);
    107 		else
    108 			break;
    109 	}
    110 
    111 	if (visible(self, trail[marker]))
    112 	{
    113 		return trail[marker];
    114 	}
    115 
    116 	if (visible(self, trail[PREV(marker)]))
    117 	{
    118 		return trail[PREV(marker)];
    119 	}
    120 
    121 	return trail[marker];
    122 }
    123 
    124 edict_t *PlayerTrail_PickNext (edict_t *self)
    125 {
    126 	int		marker;
    127 	int		n;
    128 
    129 	if (!trail_active)
    130 		return NULL;
    131 
    132 	for (marker = trail_head, n = TRAIL_LENGTH; n; n--)
    133 	{
    134 		if(trail[marker]->timestamp <= self->monsterinfo.trail_time)
    135 			marker = NEXT(marker);
    136 		else
    137 			break;
    138 	}
    139 
    140 	return trail[marker];
    141 }
    142 
    143 edict_t *PlayerTrail_LastSpot (void)
    144 {
    145 	return trail[PREV(trail_head)];
    146 }