Corrected Vacuum Extreme behavior (#2526)

* Fixes #2497.
* Vacuum Extreme will now pull players into the center.
* Vacuum Extreme should only pull in players that stop within it's AoE.
* It will now ignore "no knockback" bonuses players have.
Thanks to @esu1214, @cydh and @exneval!

src/map/skill.cpp

@@ -14290,9 +14290,9 @@ int skill_unit_onplace_timer(struct skill_unit *unit, struct block_list *bl, t_t
 			if (tsc && (tsc->data[SC_HALLUCINATIONWALK] || tsc->data[SC_HOVERING] || tsc->data[SC_VACUUM_EXTREME] ||
 				(tsc->data[SC_VACUUM_EXTREME_POSTDELAY] && tsc->data[SC_VACUUM_EXTREME_POSTDELAY]->val2 == sg->group_id))) // Ignore post delay from other vacuum (this will make stack effect enabled)
 				return 0;
-			else
-				// Apply effect and suck targets one-by-one each n seconds
-				sc_start4(ss, bl, SC_VACUUM_EXTREME, 100, sg->skill_lv, sg->group_id, (sg->val1<<16)|(sg->val2), ++sg->val3*500, (sg->limit - DIFF_TICK(tick, sg->tick)));
+
+			if (unit_bl2ud(bl)->walktimer == INVALID_TIMER) // Apply effect and suck non-walking targets one-by-one each n seconds
+				sc_start4(ss, bl, type, 100, sg->skill_lv, sg->group_id, (sg->val1<<16)|(sg->val2), ++sg->val3*500, (sg->limit - DIFF_TICK(tick, sg->tick)));
 			break;
 
 		case UNT_BANDING:

src/map/status.cpp

@@ -11110,12 +11110,11 @@ int status_change_start(struct block_list* src, struct block_list* bl,enum sc_ty
 			break;
 		case SC_VACUUM_EXTREME:
 			// Suck target at n second, only if the n second is lower than the duration
-			// Doesn't apply to BL_PC
-			if (bl->type != BL_PC && val4 < tick && !unit_blown_immune(bl,0x1) && status_has_mode(status,MD_CANMOVE)) {
+			// Does not suck targets on no-knockback maps
+			if (val4 < tick && unit_blown_immune(bl, 0x9) == UB_KNOCKABLE) {
 				tick_time = val4;
 				val4 = tick - tick_time;
-			}
-			else
+			} else
 				val4 = 0;
 			break;
 		case SC_FIRE_INSIGNIA:
@@ -11500,7 +11499,7 @@ int status_change_start(struct block_list* src, struct block_list* bl,enum sc_ty
 			unit_stop_attack(bl);
 			break;
 		case SC_VACUUM_EXTREME:
-			if (bl->type != BL_PC && !unit_blown_immune(bl,0x1)) {
+			if (bl->type != BL_PC && unit_blown_immune(bl, 0x1) == UB_KNOCKABLE) {
 				unit_stop_walking(bl,1);
 				unit_stop_attack(bl);
 			}

src/map/unit.cpp

@@ -1125,6 +1125,7 @@ int unit_blown(struct block_list* bl, int dx, int dy, int count, enum e_skill_bl
  *		0x1 - Offensive (not set: self skill, e.g. Backslide)
  *		0x2 - Knockback type (not set: Stop type, e.g. Ankle Snare)
  *		0x4 - Boss attack
+ *		0x8 - Ignore target player 'special_state.no_knockback'
  * @return reason for immunity
  *		UB_KNOCKABLE - can be knocked back / stopped
  *		UB_NO_KNOCKBACK_MAP - at WOE/BG map
@@ -1153,7 +1154,7 @@ enum e_unit_blown unit_blown_immune(struct block_list* bl, uint8 flag)
 				if( !(flag&0x4) && sd->sc.data[SC_BASILICA] && sd->sc.data[SC_BASILICA]->val4 == sd->bl.id)
 					return UB_TARGET_BASILICA;
 				// Target has special_state.no_knockback (equip)
-				if( (flag&(0x1|0x2)) && sd->special_state.no_knockback )
+				if( (flag&(0x1|0x2)) && !(flag&0x8) && sd->special_state.no_knockback )
 					return UB_TARGET_NO_KNOCKBACK;
 			}
 			break;