NPC_RUN, Monster Skill Interval (#8302)

- Monsters will now properly run away when using NPC_RUN (fixes #7941)
- Introduced a new function unit_get_walkpath_time that returns the time the unit needs to walk its current walkpath
  * This is now used for NPC_RUN and random walking
- Fixed an issue with mismatching timer warnings when a monster casts NPC_RUN multiple times in row

- Monsters will now always attempt to use non-berserk-state skills once per second (fixes #1700)
  * This completely replaces the "ugly" solution to use a walk_count for idle, walk and chase skills
  * This interval is now a lot more accurate and no longer influenced by external factors such as canact delay
  * This interval is now also used for lazy monsters rather than MIN_MOBTHINKTIME*10 so that MIN_MOBTHINKTIME can be reduced without having to worry about skills being cast more often
  * Angry skills no longer replace the normal attack and now follow the once per second rule; they will always first be attempted at the end of the walk delay after a normal attack
- The special follow-up attack skill monsters use when you move out of their attack range, now is only used when they are in Angry state
  * Also fixed a bug that this was checked every 100ms until the monster used a skill, instead of just once per second

- Monsters now can use chase skills even before they start moving (assuming one second has already passed since last skill check)
- Removed "hack" to make monsters cast chase skills when trapped in icewall
  * This was solved by implementing checking for chase skills before starting to move

- Monsters will now receive an aMotion walk delay after having used a skill
- A monster that could not walk randomly because of walk delay will now walk immediately once the walk delay expires
- Using angry or berserk skills will now set a monster's attack delay

conf/battle/skill.conf

@@ -26,8 +26,8 @@ min_skill_delay_limit: 100
 
 // This delay is the min 'can't walk delay' of all skills.
 // NOTE: Do not set this too low, if a character starts moving too soon after 
-// doing a skill, the client will not update this, and the player/mob will 
-// appear to "teleport" afterwards.
+// doing a skill, the client will not update this, and the player will appear
+// to "teleport" afterwards. Monsters use AttackMotion instead.
 default_walk_delay: 300
 
 // Completely disable skill delay of the following types (Note 3)

src/map/mob.cpp

@@ -45,8 +45,6 @@ using namespace rathena;
 
 #define ACTIVE_AI_RANGE 2	//Distance added on top of 'AREA_SIZE' at which mobs enter active AI mode.
 
-#define IDLE_SKILL_INTERVAL 10	//Active idle skills should be triggered every 1 second (1000/MIN_MOBTHINKTIME)
-
 const t_tick MOB_MAX_DELAY = 24 * 3600 * 1000;
 #define RUDE_ATTACKED_COUNT 1	//After how many rude-attacks should the skill be used?
 
@@ -1165,6 +1163,7 @@ int mob_spawn (struct mob_data *md)
 	md->dmgtick = tick - 5000;
 	md->last_pcneartime = 0;
 	md->last_canmove = tick;
+	md->last_skillcheck = 0;
 
 	t_tick c = tick - MOB_MAX_DELAY;
 
@@ -1522,14 +1521,17 @@ int mob_unlocktarget(struct mob_data *md, t_tick tick)
 			break;
 		}
 		// Idle skill.
-		if (!(++md->ud.walk_count%IDLE_SKILL_INTERVAL) && mobskill_use(md, tick, -1))
+		if (DIFF_TICK(tick, md->last_skillcheck) >= MOB_SKILL_INTERVAL && mobskill_use(md, tick, -1))
 			break;
 		//Random walk.
 		if (!md->master_id &&
 			DIFF_TICK(md->next_walktime, tick) <= 0 &&
 			!mob_randomwalk(md,tick))
 			//Delay next random walk when this one failed.
-			md->next_walktime = tick+rnd()%1000;
+			if (md->next_walktime < md->ud.canmove_tick)
+				md->next_walktime = md->ud.canmove_tick;
+			else
+				md->next_walktime = tick+rnd()%1000;
 		break;
 	default:
 		mob_stop_attack(md);
@@ -1563,8 +1565,7 @@ int mob_unlocktarget(struct mob_data *md, t_tick tick)
 int mob_randomwalk(struct mob_data *md,t_tick tick)
 {
 	const int d=7;
-	int i,c,r,rdir,dx,dy,max;
-	int speed;
+	int i,r,rdir,dx,dy,max;
 
 	nullpo_ret(md);
 
@@ -1648,16 +1649,9 @@ int mob_randomwalk(struct mob_data *md,t_tick tick)
 		}
 		return 0;
 	}
-	speed=status_get_speed(&md->bl);
-	for(i=c=0;i<md->ud.walkpath.path_len;i++){	// The next walk start time is calculated.
-		if( direction_diagonal( md->ud.walkpath.path[i] ) )
-			c+=speed*MOVE_DIAGONAL_COST/MOVE_COST;
-		else
-			c+=speed;
-	}
 	md->state.skillstate=MSS_WALK;
 	md->move_fail_count=0;
-	md->next_walktime = tick+rnd()%1000+MIN_RANDOMWALKTIME+c;
+	md->next_walktime = tick+rnd()%1000+MIN_RANDOMWALKTIME + unit_get_walkpath_time(md->bl);
 	return 1;
 }
 
@@ -1917,8 +1911,23 @@ static bool mob_ai_sub_hard(struct mob_data *md, t_tick tick)
 		return true;
 	}
 
-	//Attempt to attack.
-	//At this point we know the target is attackable, we just gotta check if the range matches.
+	// At this point we know the target is attackable, attempt to attack
+
+	// Monsters in angry state, after having used a normal attack, will always attempt a skill
+	if (md->ud.walktimer == INVALID_TIMER && md->state.skillstate == MSS_ANGRY && md->ud.skill_id == 0)
+	{
+		// Only use skill if able to walk on next tick and not attempted a skill the last second
+		if (DIFF_TICK(md->ud.canmove_tick, tick) <= MIN_MOBTHINKTIME && DIFF_TICK(tick, md->last_skillcheck) >= MOB_SKILL_INTERVAL){
+			if (mobskill_use(md, tick, -1)) {
+				// After the monster used an angry skill, it will not attack for aDelay
+				// Setting the delay here because not all monster skill use situations will cause an attack delay
+				md->ud.attackabletime = tick + md->status.adelay;
+				return true;
+			}
+		}
+	}
+
+	// Normal attack / berserk skill is only used when target is in range
 	if (battle_check_range(&md->bl, tbl, md->status.rhw.range) && !(md->sc.option&OPTION_HIDE))
 	{	//Target within range and able to use normal attack, engage
 		if (md->ud.target != tbl->id || md->ud.attacktimer == INVALID_TIMER) 
@@ -1940,16 +1949,6 @@ static bool mob_ai_sub_hard(struct mob_data *md, t_tick tick)
 		return true;
 	}
 
-	//Monsters in berserk state, unable to use normal attacks, will always attempt a skill
-	if(md->ud.walktimer == INVALID_TIMER && (md->state.skillstate == MSS_BERSERK || md->state.skillstate == MSS_ANGRY)) 
-	{
-		if (DIFF_TICK(md->ud.canmove_tick, tick) <= MIN_MOBTHINKTIME && DIFF_TICK(md->ud.canact_tick, tick) < -MIN_MOBTHINKTIME*IDLE_SKILL_INTERVAL) 
-		{ //Only use skill if able to walk on next tick and not used a skill the last second
-			if (mobskill_use(md, tick, -1))
-				return true;
-		}
-	}
-
 	//Target still in attack range, no need to chase the target
 	if(battle_check_range(&md->bl, tbl, md->status.rhw.range))
 		return true;
@@ -1971,7 +1970,7 @@ static bool mob_ai_sub_hard(struct mob_data *md, t_tick tick)
 			else {
 				// Use idle skill but keep target for now
 				md->state.skillstate = MSS_IDLE;
-				if (!(++md->ud.walk_count%IDLE_SKILL_INTERVAL))
+				if (DIFF_TICK(tick, md->last_skillcheck) >= MOB_SKILL_INTERVAL)
 					mobskill_use(md, tick, -1);
 			}
 		}
@@ -1986,10 +1985,24 @@ static bool mob_ai_sub_hard(struct mob_data *md, t_tick tick)
 		return true;
 
 	//Follow up if possible.
-	//Hint: Chase skills are handled in the walktobl routine
-	if(!mob_can_reach(md, tbl, md->min_chase) ||
-		!unit_walktobl(&md->bl, tbl, md->status.rhw.range, 2))
-		mob_unlocktarget(md,tick);
+	if (!mob_can_reach(md, tbl, md->min_chase)) {
+		mob_unlocktarget(md, tick);
+		return true;
+	}
+	// Monsters can use chase skills before starting to walk
+	// So we need to change the state and check for a skill here already
+	// But only use skill if able to walk on next tick and not attempted a skill the last second
+	// Skills during movement are handled in the walktobl routine
+	if (md->ud.walktimer == INVALID_TIMER
+		&& DIFF_TICK(md->ud.canmove_tick, tick) <= MIN_MOBTHINKTIME
+		&& DIFF_TICK(tick, md->last_skillcheck) >= MOB_SKILL_INTERVAL) {
+		md->state.skillstate = md->state.aggressive ? MSS_FOLLOW : MSS_RUSH;
+		if (mobskill_use(md, tick, -1))
+			return true;
+	}
+
+	if(!unit_walktobl(&md->bl, tbl, md->status.rhw.range, 2))
+		mob_unlocktarget(md, tick);
 
 	return true;
 }
@@ -2063,7 +2076,7 @@ static int mob_ai_sub_lazy(struct mob_data *md, va_list args)
 	//Clean the spotted log
 	mob_clean_spotted(md);
 
-	if(DIFF_TICK(tick,md->last_thinktime)< 10*MIN_MOBTHINKTIME)
+	if(DIFF_TICK(tick,md->last_thinktime) < MOB_SKILL_INTERVAL)
 		return 0;
 
 	md->last_thinktime=tick;
@@ -3752,8 +3765,9 @@ int mobskill_use(struct mob_data *md, t_tick tick, int event, int64 damage)
 	if (!battle_config.mob_skill_rate || md->ud.skilltimer != INVALID_TIMER || ms.empty() || status_has_mode(&md->status,MD_NOCAST))
 		return 0;
 
-	if (event == -1 && DIFF_TICK(md->ud.canact_tick, tick) > 0)
-		return 0; //Skill act delay only affects non-event skills.
+	// Monsters check their non-attack-state skills once per second, but we ignore this for events for now
+	if (event == -1)
+		md->last_skillcheck = tick;
 
 	//Pick a starting position and loop from that.
 	i = battle_config.mob_ai&0x100?rnd()%ms.size():0;

src/map/mob.hpp

@@ -38,6 +38,9 @@ const t_tick MIN_MOBLINKTIME = 1000;
 //Min time between random walks
 const t_tick MIN_RANDOMWALKTIME = 4000;
 
+// How often a monster will check for using a skill on non-attack states (in ms)
+const t_tick MOB_SKILL_INTERVAL = 1000;
+
 //Distance that slaves should keep from their master.
 #define MOB_SLAVEDISTANCE 2
 
@@ -359,7 +362,7 @@ struct mob_data {
 	int areanpc_id; //Required in OnTouchNPC (to avoid multiple area touchs)
 	int bg_id; // BattleGround System
 
-	t_tick next_walktime,last_thinktime,last_linktime,last_pcneartime,dmgtick,last_canmove;
+	t_tick next_walktime,last_thinktime,last_linktime,last_pcneartime,dmgtick,last_canmove,last_skillcheck;
 	short move_fail_count;
 	short lootitem_count;
 	short min_chase;

src/map/skill.cpp

@@ -9938,7 +9938,15 @@ int skill_castend_nodamage_id (struct block_list *src, struct block_list *bl, ui
 			if (tbl) {
 				md->state.can_escape = 1;
 				mob_unlocktarget(md, tick);
-				unit_escape(src, tbl, skill_lv > 1 ? skill_lv : AREA_SIZE, 2); // Send distance in skill level > 1
+				// Official distance is 7, if level > 1, distance = level
+				t_tick time = unit_escape(src, tbl, skill_lv > 1 ? skill_lv : 7, 2);
+
+				if (time) {
+					// Need to set state here as it's not set otherwise
+					md->state.skillstate = MSS_WALK;
+					// Set AI to inactive for the duration of this movement
+					md->last_thinktime = tick + time;
+				}
 			}
 		}
 		break;
@@ -13421,8 +13429,14 @@ TIMER_FUNC(skill_castend_id){
 			}
 			}
 		}
-		if (skill_get_state(ud->skill_id) != ST_MOVE_ENABLE)
-			unit_set_walkdelay(src, tick, battle_config.default_walk_delay+skill_get_walkdelay(ud->skill_id, ud->skill_lv), 1);
+		if (skill_get_state(ud->skill_id) != ST_MOVE_ENABLE) {
+			// When monsters used a skill they won't walk for amotion, this does not apply to players
+			// This is also important for monster skill usage behavior
+			if (src->type == BL_MOB)
+				unit_set_walkdelay(src, tick, max((int)status_get_amotion(src), skill_get_walkdelay(ud->skill_id, ud->skill_lv)), 1);
+			else
+				unit_set_walkdelay(src, tick, battle_config.default_walk_delay + skill_get_walkdelay(ud->skill_id, ud->skill_lv), 1);
+		}
 
 		if(battle_config.skill_log && battle_config.skill_log&src->type)
 			ShowInfo("Type %d, ID %d skill castend id [id =%d, lv=%d, target ID %d]\n",
@@ -13636,7 +13650,12 @@ TIMER_FUNC(skill_castend_pos){
 //				break;
 //			}
 //		}
-		unit_set_walkdelay(src, tick, battle_config.default_walk_delay+skill_get_walkdelay(ud->skill_id, ud->skill_lv), 1);
+		// When monsters used a skill they won't walk for amotion, this does not apply to players
+		// This is also important for monster skill usage behavior
+		if (src->type == BL_MOB)
+			unit_set_walkdelay(src, tick, max((int)status_get_amotion(src), skill_get_walkdelay(ud->skill_id, ud->skill_lv)), 1);
+		else
+			unit_set_walkdelay(src, tick, battle_config.default_walk_delay + skill_get_walkdelay(ud->skill_id, ud->skill_lv), 1);
 		map_freeblock_lock();
 		skill_castend_pos2(src,ud->skillx,ud->skilly,ud->skill_id,ud->skill_lv,tick,0);
 

src/map/skill.hpp

@@ -182,10 +182,6 @@ enum e_skill_unit_flag : uint8 {
 	UF_MAX,
 };
 
-/// Walk intervals at which chase-skills are attempted to be triggered.
-/// If you change this, make sure it's an odd value (for icewall block behavior).
-#define WALK_SKILL_INTERVAL 5
-
 /// Time that's added to canact delay on castbegin and substracted on castend
 /// This is to prevent hackers from sending a skill packet after cast but before a timer triggers castend
 const t_tick SECURITY_CASTTIME = 100;

src/map/unit.cpp

@@ -448,11 +448,10 @@ static TIMER_FUNC(unit_walktoxy_timer)
 		//Needs to be done here so that rudeattack skills are invoked
 		md->walktoxy_fail_count++;
 		clif_fixpos(bl);
-		//Monsters in this situation first use a chase skill, then unlock target and then use an idle skill
-		if (!(++ud->walk_count%WALK_SKILL_INTERVAL))
-			mobskill_use(md, tick, -1);
+		// Monsters in this situation will unlock target and then attempt an idle skill
+		// When they start chasing again, they will check for a chase skill before returning here
 		mob_unlocktarget(md, tick);
-		if (!(++ud->walk_count%WALK_SKILL_INTERVAL))
+		if (DIFF_TICK(tick, md->last_skillcheck) >= MOB_SKILL_INTERVAL)
 			mobskill_use(md, tick, -1);
 		return 0;
 	}
@@ -463,7 +462,6 @@ static TIMER_FUNC(unit_walktoxy_timer)
 	x += dx;
 	y += dy;
 	map_moveblock(bl, x, y, tick);
-	ud->walk_count++; // Walked cell counter, to be used for walk-triggered skills. [Skotlex]
 
 	if (bl->x != x || bl->y != y || ud->walktimer != INVALID_TIMER)
 		return 0; // map_moveblock has altered the object beyond what we expected (moved/warped it)
@@ -542,8 +540,11 @@ static TIMER_FUNC(unit_walktoxy_timer)
 				md->min_chase--;
 			// Walk skills are triggered regardless of target due to the idle-walk mob state.
 			// But avoid triggering on stop-walk calls.
+			// Monsters use walk/chase skills every second, but we only get here every "speed" ms
+			// To make sure we check one skill per second on average, we substract half the speed as ms
 			if(!ud->state.force_walk && tid != INVALID_TIMER &&
-				!(ud->walk_count%WALK_SKILL_INTERVAL) &&
+				DIFF_TICK(tick, md->last_skillcheck) > MOB_SKILL_INTERVAL - md->status.speed / 2 &&
+				DIFF_TICK(tick, md->last_thinktime) > 0 &&
 				map[bl->m].users > 0 &&
 				mobskill_use(md, tick, -1)) {
 				if (!(ud->skill_id == NPC_SELFDESTRUCTION && ud->skilltimer != INVALID_TIMER)
@@ -616,6 +617,12 @@ static TIMER_FUNC(unit_walktoxy_timer)
 		speed = status_get_speed(bl);
 
 	if(speed > 0) {
+		// For some reason sometimes the walk timer is not empty here
+		// TODO: Need to check why (e.g. when the monster spams NPC_RUN)
+		if (ud->walktimer != INVALID_TIMER) {
+			delete_timer(ud->walktimer, unit_walktoxy_timer);
+			ud->walktimer = INVALID_TIMER;
+		}
 		ud->walktimer = add_timer(tick+speed,unit_walktoxy_timer,id,speed);
 		if( md && DIFF_TICK(tick,md->dmgtick) < 3000 ) // Not required not damaged recently
 			clif_move(ud);
@@ -1004,22 +1011,47 @@ bool unit_run(struct block_list *bl, map_session_data *sd, enum sc_type type)
 	return true;
 }
 
+/**
+ * Returns duration of an object's current walkpath
+ * @param bl: Object that is moving
+ * @return Duration of the walkpath
+ */
+t_tick unit_get_walkpath_time(struct block_list& bl)
+{
+	t_tick time = 0;
+	unsigned short speed = status_get_speed(&bl);
+	struct unit_data* ud = unit_bl2ud(&bl);
+
+	// The next walk start time is calculated.
+	for (uint8 i = 0; i < ud->walkpath.path_len; i++) {
+		if (direction_diagonal(ud->walkpath.path[i]))
+			time += speed * MOVE_DIAGONAL_COST / MOVE_COST;
+		else
+			time += speed;
+	}
+
+	return time;
+}
+
 /**
  * Makes unit attempt to run away from target using hard paths
  * @param bl: Object that is running away from target
  * @param target: Target
  * @param dist: How far bl should run
  * @param flag: unit_walktoxy flag
- * @return 1: Success 0: Fail
+ * @return The duration the unit will run (0 on fail)
  */
-int unit_escape(struct block_list *bl, struct block_list *target, short dist, uint8 flag)
+t_tick unit_escape(struct block_list *bl, struct block_list *target, short dist, uint8 flag)
 {
 	uint8 dir = map_calc_dir(target, bl->x, bl->y);
 
 	while( dist > 0 && map_getcell(bl->m, bl->x + dist*dirx[dir], bl->y + dist*diry[dir], CELL_CHKNOREACH) )
 		dist--;
 
-	return ( dist > 0 && unit_walktoxy(bl, bl->x + dist*dirx[dir], bl->y + dist*diry[dir], flag) );
+	if (dist > 0 && unit_walktoxy(bl, bl->x + dist * dirx[dir], bl->y + dist * diry[dir], flag))
+		return unit_get_walkpath_time(*bl);
+
+	return 0;
 }
 
 /**
@@ -2784,10 +2816,14 @@ static int unit_attack_timer_sub(struct block_list* src, int tid, t_tick tick)
 			unit_stop_walking(src,1);
 
 		if(md) {
-			//First attack is always a normal attack
-			if(md->state.skillstate == MSS_ANGRY || md->state.skillstate == MSS_BERSERK) {
-				if (mobskill_use(md,tick,-1))
+			// Berserk skills can replace normal attacks except for the first attack
+			// If this is the first attack, the state is not Berserk yet, so the skill check is skipped
+			if(md->state.skillstate == MSS_BERSERK) {
+				if (mobskill_use(md, tick, -1)) {
+					// Setting the delay here because not all monster skill use situations will cause an attack delay
+					ud->attackabletime = tick + sstatus->adelay;
 					return 1;
+				}
 			}
 			// Set mob's ANGRY/BERSERK states.
 			md->state.skillstate = md->state.aggressive?MSS_ANGRY:MSS_BERSERK;
@@ -2818,6 +2854,7 @@ static int unit_attack_timer_sub(struct block_list* src, int tid, t_tick tick)
 			return 1;
 
 		ud->attackabletime = tick + sstatus->adelay;
+		ud->skill_id = 0;
 
 		// You can't move if you can't attack neither.
 		if (src->type&battle_config.attack_walk_delay)

src/map/unit.hpp

@@ -44,7 +44,6 @@ struct unit_data {
 	t_tick canmove_tick;
 	bool immune_attack; ///< Whether the unit is immune to attacks
 	uint8 dir;
-	unsigned char walk_count;
 	unsigned char target_count;
 	struct s_udState {
 		unsigned change_walk_target : 1 ;
@@ -122,7 +121,8 @@ bool unit_can_move(struct block_list *bl);
 int unit_is_walking(struct block_list *bl);
 int unit_set_walkdelay(struct block_list *bl, t_tick tick, t_tick delay, int type);
 
-int unit_escape(struct block_list *bl, struct block_list *target, short dist, uint8 flag = 0);
+t_tick unit_get_walkpath_time(struct block_list& bl);
+t_tick unit_escape(struct block_list *bl, struct block_list *target, short dist, uint8 flag = 0);
 
 // Instant unit changes
 bool unit_movepos(struct block_list *bl, short dst_x, short dst_y, int easy, bool checkpath);