- Merged config option knockback_left from Hercules

  * Now the default direction is "east" and consequently the knockback direction is "west" when standing
  * This means if the source cell (ground target center or position of caster) is on the same cell as the target, it will be knocked back to the west
  * This also can effect other things like how an object is placed when cast on the cell you are currently standing on
  * If you disable the option it will use the old behavior and use the direction of the unit as default direction (and backwards as knock direction)
  * Special thanks to kisuka and Michieru for the original implementation: https://github.com/HerculesWS/Hercules/commit/2b8d5013ea8ba9904d157c773f12495bbca8ca80
- Optimized the knockback / instant movement code
  * clif_blown will now call both clif_slide and then clif_fixpos, this is what Aegis does when any instant movement effect occurs and ensures proper updating of the position
  * skill_blown will call clif_blown and ensures the correct client information already, so it's no longer necessary to manually call clif_slide and clif_fixpos after it
  * replaced all calls of clif_slide and then clif_fixpos in row with a single call of clif_blown, makes the code look a lot cleaner
  * I tested over 20 knockback situations including knockback of frozen target and it worked fine for me, please report if there is still anything wrong (was why fixpos commented in the first place?)

conf/battle/battle.conf

@@ -142,6 +142,10 @@ arrow_decrement: 1
 // This setting also affects autospellwhenhit.
 autospell_check_range: no
 
+// If both the attacker and the target are on the same tile, should the target be knocked back to the left?
+// Official behavior is "yes", setting this to "no" will knock the target back behind the attacker.
+knockback_left: yes
+
 // Can players use Falcons and Wargs at the same time? (Note 1)
 // This is not allowed on official servers.
 warg_can_falcon: no

src/map/battle.c

@@ -1216,8 +1216,7 @@ int64 battle_calc_damage(struct block_list *src,struct block_list *bl,struct Dam
 			uint8 dir = map_calc_dir(bl, src->x, src->y);
 
 			if( unit_movepos(bl, src->x-dx[dir], src->y-dy[dir], 1, 1) ) {
-				clif_slide(bl,src->x, src->y);
-				clif_fixpos(bl); // The official server sends these two packets
+				clif_blown(bl);
 				unit_setdir(bl, dir);
 			}
 			d->dmg_lv = ATK_DEF;
@@ -7802,6 +7801,7 @@ static const struct _battle_data {
 	{ "invincible.nodamage",                &battle_config.invincible_nodamage,             0,      0,      1,              },
 	{ "mob_slave_keep_target",              &battle_config.mob_slave_keep_target,           0,      0,      1,              },
 	{ "autospell_check_range",              &battle_config.autospell_check_range,           0,      0,      1,              },
+	{ "knockback_left",                     &battle_config.knockback_left,                  1,      0,      1,              },
 	{ "client_reshuffle_dice",              &battle_config.client_reshuffle_dice,           0,      0,      1,              },
 	{ "client_sort_storage",                &battle_config.client_sort_storage,             0,      0,      1,              },
 	{ "feature.buying_store",               &battle_config.feature_buying_store,            1,      0,      1,              },

src/map/battle.h

@@ -467,6 +467,7 @@ extern struct Battle_Config
 	int invincible_nodamage;
 	int mob_slave_keep_target;
 	int autospell_check_range;	//Enable range check for autospell bonus. [L0ne_W0lf]
+	int knockback_left;
 	int client_reshuffle_dice;  // Reshuffle /dice
 	int client_sort_storage;
 	int feature_buying_store;

src/map/clif.c

@@ -1718,10 +1718,12 @@ void clif_changemapserver(struct map_session_data* sd, unsigned short map_index,
 }
 
 
+/// In many situations (knockback, backslide, etc.) Aegis sends both clif_slide and clif_fixpos
+/// This function combines both calls and allows to simplify the calling code
 void clif_blown(struct block_list *bl)
 {
 	clif_slide(bl, bl->x, bl->y);
-	//clif_fixpos(bl); //Aegis packets says fixpos, but it's unsure whether slide works better or not.
+	clif_fixpos(bl);
 }
 
 

src/map/map.c

@@ -2580,8 +2580,9 @@ uint8 map_calc_dir(struct block_list* src, int16 x, int16 y)
 	dy = y-src->y;
 	if( dx == 0 && dy == 0 )
 	{	// both are standing on the same spot
-		//dir = 6; // aegis-style, makes knockback default to the left
-		dir = unit_getdir(src); // athena-style, makes knockback default to behind 'src'
+		// aegis-style, makes knockback default to the left
+		// athena-style, makes knockback default to behind 'src'
+		dir = (battle_config.knockback_left ? 6 : unit_getdir(src));
 	}
 	else if( dx >= 0 && dy >=0 )
 	{	// upper-right

src/map/skill.c

@@ -2793,10 +2793,8 @@ void skill_attack_blow(struct block_list *src, struct block_list *dsrc, struct b
 				dir_ka = -1;
 
 				// Move attacker to the target position after knocked back
-				if ((target->x != x || target->y != y) && unit_movepos(src,target->x,target->y,1,1)) {
-					clif_slide(src, target->x, target->y);
-					clif_fixpos(src);
-				}
+				if ((target->x != x || target->y != y) && unit_movepos(src,target->x,target->y,1,1))
+					clif_blown(src);
 			}
 			break;
 		case RL_R_TRIP:
@@ -2804,11 +2802,11 @@ void skill_attack_blow(struct block_list *src, struct block_list *dsrc, struct b
 				skill_addtimerskill(src, tick + status_get_amotion(src), target->id, 0, 0, RL_R_TRIP_PLUSATK, skill_lv, BF_WEAPON, flag|SD_ANIMATION);
 			break;
 		case RL_SLUGSHOT:
-			skill_blown(dsrc,target,blewcount,dir, 0x0);
+			skill_blown(dsrc,target,blewcount,dir, 0);
 			skill_addtimerskill(src, tick + status_get_amotion(src), target->id, 0, 0, skill_id, skill_lv, skill_get_type(skill_id), flag|SD_ANIMATION);
 			break;
 		default:
-			skill_blown(dsrc,target,blewcount,dir, 0x0 );
+			skill_blown(dsrc,target,blewcount,dir, 0);
 			if (!blewcount && target->type == BL_SKILL && damage > 0) {
 				TBL_SKILL *su = (TBL_SKILL*)target;
 				if (su->group && su->group->skill_id == HT_BLASTMINE)
@@ -3817,7 +3815,7 @@ static int skill_timerskill(int tid, unsigned int tick, int id, intptr_t data)
 						struct status_change* sc = status_get_sc(src);
 						if( ( tsc && tsc->option&OPTION_HIDE ) ||
 							( sc && sc->option&OPTION_HIDE ) ){
-							skill_blown(src,target,skill_get_blewcount(skl->skill_id, skl->skill_lv), -1, 0x0 );
+							skill_blown(src,target,skill_get_blewcount(skl->skill_id, skl->skill_lv), -1, 0);
 							break;
 						}
 						skill_attack(skl->type,src,src,target,skl->skill_id,skl->skill_lv,tick,skl->flag);
@@ -4209,10 +4207,8 @@ int skill_castend_damage_id (struct block_list* src, struct block_list *bl, uint
 		uint8 dir = map_calc_dir(bl, src->x, src->y);
 
 		// teleport to target (if not on WoE grounds)
-		if( !map_flag_gvg(src->m) && !map[src->m].flag.battleground && unit_movepos(src, bl->x, bl->y, 0, 1) ) {
-			clif_slide(src, bl->x, bl->y);
-			clif_fixpos(src);
-		}
+		if( !map_flag_gvg(src->m) && !map[src->m].flag.battleground && unit_movepos(src, bl->x, bl->y, 0, 1) )
+			clif_blown(src);
 
 		// cause damage and knockback if the path to target was a straight one
 		if( path )
@@ -4327,8 +4323,7 @@ int skill_castend_damage_id (struct block_list* src, struct block_list *bl, uint
 			// Ashura Strike still has slide effect in GVG
 			if ((mbl == src || (!map_flag_gvg2(src->m) && !map[src->m].flag.battleground)) &&
 				unit_movepos(src, mbl->x + x, mbl->y + y, 1, 1)) {
-				clif_slide(src, mbl->x, mbl->y);
-				clif_fixpos(src);
+				clif_blown(src);
 				clif_spiritball(src);
 			}
 		}
@@ -4724,8 +4719,7 @@ int skill_castend_damage_id (struct block_list* src, struct block_list *bl, uint
 			y = 0;
 		// Doesn't have slide effect in GVG
 		if (!map_flag_gvg2(src->m) && !map[src->m].flag.battleground && unit_movepos(src, bl->x + x, bl->y + y, 1, 1)) {
-			clif_slide(src, bl->x, bl->y);
-			clif_fixpos(src);
+			clif_blown(src);
 			clif_spiritball(src);
 		}
 		skill_attack(BF_MISC, src, src, bl, skill_id, skill_lv, tick, flag);
@@ -4796,8 +4790,7 @@ int skill_castend_damage_id (struct block_list* src, struct block_list *bl, uint
 			short x, y;
 			map_search_freecell(bl, 0, &x, &y, 1, 1, 0);
 			if (unit_movepos(src, x, y, 0, 0)) {
-				clif_slide(src, src->x, src->y);
-				clif_fixpos(src);
+				clif_blown(src);
 			}
 		}
 		status_change_end(src, SC_HIDING, INVALID_TIMER);
@@ -4842,8 +4835,7 @@ int skill_castend_damage_id (struct block_list* src, struct block_list *bl, uint
 			else y = 0;
 
 			if( unit_movepos(src, bl->x+x, bl->y+y, 1, 1) ) {
-				clif_slide(src, bl->x, bl->y);
-				clif_fixpos(src);
+				clif_blown(src);
 				skill_attack(BF_WEAPON,src,src,bl,skill_id,skill_lv,tick,flag);
 				if( rnd()%100 < 4 * skill_lv )
 					skill_castend_damage_id(src,bl,GC_CROSSIMPACT,skill_lv,tick,flag);
@@ -5059,8 +5051,7 @@ int skill_castend_damage_id (struct block_list* src, struct block_list *bl, uint
 			uint8 dir = map_calc_dir(bl, src->x, src->y);
 
 			if( unit_movepos(src, bl->x+x[dir], bl->y+y[dir], 1, 1) ) {
-				clif_slide(src, bl->x, bl->y);
-				clif_fixpos(src);
+				clif_blown(src);
 				skill_attack(BF_WEAPON, src, src, bl, skill_id, skill_lv, tick, flag);
 			}
 			break;
@@ -5136,10 +5127,8 @@ int skill_castend_damage_id (struct block_list* src, struct block_list *bl, uint
 		}
 		break;
 	case LG_PINPOINTATTACK:
-		if( !map_flag_gvg(src->m) && !map[src->m].flag.battleground && unit_movepos(src, bl->x, bl->y, 1, 1) ) {
-			clif_slide(src, bl->x, bl->y);
-			clif_fixpos(src);
-		}
+		if( !map_flag_gvg(src->m) && !map[src->m].flag.battleground && unit_movepos(src, bl->x, bl->y, 1, 1) )
+			clif_blown(src);
 		skill_attack(BF_WEAPON,src,src,bl,skill_id,skill_lv,tick,flag);
 		break;
 
@@ -5158,10 +5147,8 @@ int skill_castend_damage_id (struct block_list* src, struct block_list *bl, uint
 		// Holds current direction of bl/target to src/attacker before the src is moved to bl location
 		dir_ka = map_calc_dir(bl, src->x, src->y);
 		// Has slide effect even in GVG
-		if( unit_movepos(src, bl->x, bl->y, 1, 1) ) {
-			clif_slide(src, bl->x, bl->y);
-			clif_fixpos(src);
-		}
+		if( unit_movepos(src, bl->x, bl->y, 1, 1) )
+			clif_blown(src);
 
 		if( flag&1 )
 			skill_attack(BF_WEAPON, src, src, bl, skill_id, skill_lv, tick, flag|SD_LEVEL);
@@ -5261,8 +5248,7 @@ int skill_castend_damage_id (struct block_list* src, struct block_list *bl, uint
 			else
 				y = 0;
 			if (unit_movepos(src,bl->x + x,bl->y + y,1,1)) {
-				clif_slide(src, bl->x, bl->y);
-				clif_fixpos(src);
+				clif_blown(src);
 				skill_attack(BF_WEAPON,src,src,bl,skill_id,skill_lv,tick,flag);
 			}
 		}
@@ -5375,8 +5361,7 @@ int skill_castend_damage_id (struct block_list* src, struct block_list *bl, uint
 			duration = max(skill_lv,(status_get_str(src)/7 - status_get_str(bl)/10))*1000; //Yommy formula
 
 			if (skill_id == MH_TINDER_BREAKER && unit_movepos(src, bl->x, bl->y, 1, 1)) {
-				clif_slide(src, bl->x, bl->y);
-				clif_fixpos(src);
+				clif_blown(src);
 				clif_skill_poseffect(src,skill_id,skill_lv,bl->x,bl->y,tick);
 			}
 			clif_skill_nodamage(src,bl,skill_id,skill_lv,
@@ -6075,8 +6060,7 @@ int skill_castend_nodamage_id (struct block_list *src, struct block_list *bl, ui
 		if( battle_check_target(src, bl, BCT_ENEMY) > 0 ) {
 			if( unit_movepos(src, bl->x, bl->y, 1, 1) ) {
 				skill_attack(BF_WEAPON,src,src,bl,skill_id,skill_lv,tick,flag);
-				clif_slide(src, bl->x, bl->y);
-				clif_fixpos(src);
+				clif_blown(src);
 			}
 		} else
 			clif_skill_fail(sd,skill_id,USESKILL_FAIL,0);
@@ -7382,10 +7366,8 @@ int skill_castend_nodamage_id (struct block_list *src, struct block_list *bl, ui
 			}
 
 			clif_skill_nodamage(src,bl,TK_HIGHJUMP,skill_lv,1);
-			if(!map_count_oncell(src->m,x,y,BL_PC|BL_NPC|BL_MOB) && map_getcell(src->m,x,y,CELL_CHKREACH) && unit_movepos(src, x, y, 1, 0)) {
-				clif_slide(src, src->x, src->y);
-				clif_fixpos(src);
-			}
+			if(!map_count_oncell(src->m,x,y,BL_PC|BL_NPC|BL_MOB) && map_getcell(src->m,x,y,CELL_CHKREACH) && unit_movepos(src, x, y, 1, 0))
+				clif_blown(src);
 		}
 		break;
 
@@ -8266,12 +8248,10 @@ int skill_castend_nodamage_id (struct block_list *src, struct block_list *bl, ui
 				skill_blockhomun_start(hd,skill_id,skill_get_time2(skill_id,skill_lv));
 			if (unit_movepos(src,bl->x,bl->y,0,0)) {
 				clif_skill_nodamage(src,src,skill_id,skill_lv,1); // Homunc
-				clif_slide(src, bl->x, bl->y);
-				clif_fixpos(src);
+				clif_blown(src);
 				if (unit_movepos(bl,x,y,0,0)) {
 					clif_skill_nodamage(bl,bl,skill_id,skill_lv,1); // Master
-					clif_slide(bl, x, y);
-					clif_fixpos(bl);
+					clif_blown(bl);
 				}
 				//TODO: Make casted skill also change its target
 				map_foreachinrange(skill_changetarget,src,AREA_SIZE,BL_CHAR,bl,src);
@@ -9051,9 +9031,7 @@ int skill_castend_nodamage_id (struct block_list *src, struct block_list *bl, ui
 	case NC_B_SIDESLIDE:
 		{
 			uint8 dir = (skill_id == NC_F_SIDESLIDE) ? (unit_getdir(src)+4)%8 : unit_getdir(src);
-			skill_blown(src,bl,skill_get_blewcount(skill_id,skill_lv),dir,0x1);
-			clif_slide(src, src->x, src->y);
-			clif_fixpos(src);
+			skill_blown(src,bl,skill_get_blewcount(skill_id,skill_lv),dir,0);
 			clif_skill_nodamage(src,bl,skill_id,skill_lv,1);
 		}
 		break;
@@ -10011,15 +9989,13 @@ int skill_castend_nodamage_id (struct block_list *src, struct block_list *bl, ui
 
 			if (unit_movepos(src,bl->x,bl->y,0,0)) {
 				clif_skill_nodamage(src,src,skill_id,skill_lv,1);
-				clif_slide(src, bl->x, bl->y);
-				clif_fixpos(src);
+				clif_blown(src);
 				sc_start(src,src,SC_CONFUSION,25,skill_lv,skill_get_time(skill_id,skill_lv));
 				if (unit_movepos(bl,x,y,0,0)) {
 					clif_skill_damage(bl,bl,tick, status_get_amotion(src), 0, -30000, 1, skill_id, -1, 6);
 					if( bl->type == BL_PC && pc_issit((TBL_PC*)bl))
 						clif_sitting(bl); //Avoid sitting sync problem
-					clif_slide(bl, x, y);
-					clif_fixpos(bl);
+					clif_blown(bl);
 					sc_start(src,bl,SC_CONFUSION,75,skill_lv,skill_get_time(skill_id,skill_lv));
 				}
 			}
@@ -10647,8 +10623,7 @@ int skill_castend_id(int tid, unsigned int tick, int id, intptr_t data)
 			else
 				y = 0;
 			if( unit_movepos(src, src->x + x, src->y + y, 1, 1) ) { //Display movement + animation.
-				clif_slide(src, src->x, src->y);
-				clif_fixpos(src);
+				clif_blown(src);
 				clif_spiritball(src);
 			}
 			clif_skill_damage(src,target,tick,sd->battle_status.amotion,0,0,1,ud->skill_id,ud->skill_lv,5);
@@ -11129,10 +11104,8 @@ int skill_castend_pos2(struct block_list* src, int x, int y, uint16 skill_id, ui
 		}
 		break;
 	case NJ_SHADOWJUMP:
-		if( !map_flag_gvg(src->m) && !map[src->m].flag.battleground && unit_movepos(src, x, y, 1, 0) ) { //You don't move on GVG grounds.
-			clif_slide(src, x, y);
-			clif_fixpos(src);
-		}
+		if( !map_flag_gvg(src->m) && !map[src->m].flag.battleground && unit_movepos(src, x, y, 1, 0) ) //You don't move on GVG grounds.
+			clif_blown(src);
 		status_change_end(src, SC_HIDING, INVALID_TIMER);
 		break;
 	case AM_SPHEREMINE:
@@ -11549,8 +11522,7 @@ int skill_castend_pos2(struct block_list* src, int x, int y, uint16 skill_id, ui
 		if (unit_movepos(src,x,y,1,1)) {
 			enum e_skill skill_use = GS_DESPERADO;
 			uint8 skill_use_lv = pc_checkskill(sd,skill_use);
-			clif_slide(src, x, y);
-			clif_fixpos(src);
+			clif_blown(src);
 			if (skill_use_lv && skill_check_condition_castend(sd,skill_use,skill_use_lv)) {
 				sd->skill_id_old = RL_FALLEN_ANGEL;
 				skill_castend_pos2(src,src->x,src->y,skill_use,skill_use_lv,tick,SD_LEVEL|SD_ANIMATION|SD_SPLASH);
@@ -12557,7 +12529,6 @@ static int skill_unit_onplace(struct skill_unit *unit, struct block_list *bl, un
 				if( i > 0 && !(status_get_mode(bl)&MD_BOSS) )
 				{ // knock-back any enemy except Boss
 					skill_blown(ss, bl, skill_get_blewcount(skill_id, sg->skill_lv), unit_getdir(bl), 0);
-					clif_fixpos(bl);
 					break;
 				}
 				if (!sce && i <= 0)
@@ -13064,7 +13035,6 @@ int skill_unit_onplace_timer(struct skill_unit *unit, struct block_list *bl, uns
 				if( i > 0 && !(status_get_mode(bl)&MD_BOSS) )
 				{ // knock-back any enemy except Boss
 					skill_blown(&unit->bl, bl, skill_get_blewcount(skill_id, sg->skill_lv), unit_getdir(bl), 0);
-					clif_fixpos(bl);
 					break;
 				}
 				if (i <= 0 && (!tsc || !tsc->data[SC_BASILICA]))
@@ -13182,7 +13152,6 @@ int skill_unit_onplace_timer(struct skill_unit *unit, struct block_list *bl, uns
 			if (status_get_mode(bl)&MD_BOSS)
 				break; // This skill doesn't affect to Boss monsters. [iRO Wiki]
 			skill_blown(&unit->bl, bl, skill_get_blewcount(sg->skill_id, sg->skill_lv), -1, 0);
-			clif_fixpos(bl);
 			skill_addtimerskill(ss, tick + 100, bl->id, unit->bl.x, unit->bl.y, sg->skill_id, sg->skill_lv, skill_get_type(sg->skill_id), 4|SD_LEVEL);
 			break;
 

src/map/unit.c

@@ -794,7 +794,6 @@ int unit_run(struct block_list *bl)
 		status_change_end(bl, SC_RUN, INVALID_TIMER);
 
 		skill_blown(bl,bl,skill_get_blewcount(TK_RUN,lv),unit_getdir(bl),0);
-		clif_fixpos(bl); // Why is a clif_slide (skill_blown) AND a fixpos needed? Ask Aegis.
 		clif_status_change(bl, SI_BUMP, 0, 0, 0, 0, 0);
 
 		return 0;