Core/Creature: Reworked creature aggro radius calculation (#20615)

* Core/Creatures: rewrote creature aggro radius calculation
* Formulas are taken from WoW Wiki

src/server/game/Entities/Creature/Creature.cpp

@@ -1646,40 +1646,44 @@ bool Creature::CheckNoGrayAggroConfig(uint32 playerLevel, uint32 creatureLevel)
 
 float Creature::GetAttackDistance(Unit const* player) const
 {
+    // WoW Wiki: the minimum radius seems to be 5 yards, while the maximum range is 45 yards
+    float maxRadius = (45.0f * sWorld->getRate(RATE_CREATURE_AGGRO));
+    float minRadius = (5.0f * sWorld->getRate(RATE_CREATURE_AGGRO));
     float aggroRate = sWorld->getRate(RATE_CREATURE_AGGRO);
-    if (aggroRate == 0)
-        return 0.0f;
+    uint8 expansionMaxLevel = uint8(GetMaxLevelForExpansion(GetCreatureTemplate()->RequiredExpansion));
+    int32 levelDifference = getLevel() - player->getLevel();
 
-    uint32 playerlevel   = player->GetLevelForTarget(this);
-    uint32 creaturelevel = GetLevelForTarget(player);
+    if (aggroRate == 0.0f)
+        return 0.0;
 
-    int32 leveldif       = int32(playerlevel) - int32(creaturelevel);
+    // The aggro radius for creatures with equal level as the player is 20 yards.
+    // The combatreach should not get taken into account for the distance so we drop it from the range (see Supremus as expample)
+    float baseAggroDistance = 20.0f - GetFloatValue(UNIT_FIELD_COMBATREACH);
 
-    // "The maximum Aggro Radius has a cap of 25 levels under. Example: A level 30 char has the same Aggro Radius of a level 5 char on a level 60 mob."
-    if (leveldif < - 25)
-        leveldif = -25;
+    // + - 1 yard for each level difference between player and creature
+    float aggroRadius = baseAggroDistance + float(levelDifference);
 
-    // "The aggro radius of a mob having the same level as the player is roughly 20 yards"
-    float RetDistance = 20;
-
-    // "Aggro Radius varies with level difference at a rate of roughly 1 yard/level"
-    // radius grow if playlevel < creaturelevel
-    RetDistance -= (float)leveldif;
-
-    if (creaturelevel+5 <= sWorld->getIntConfig(CONFIG_MAX_PLAYER_LEVEL))
+    // detect range auras
+    if (float(getLevel() + 5) <= sWorld->getIntConfig(CONFIG_MAX_PLAYER_LEVEL))
     {
-        // detect range auras
-        RetDistance += GetTotalAuraModifier(SPELL_AURA_MOD_DETECT_RANGE);
+        aggroRadius += GetTotalAuraModifier(SPELL_AURA_MOD_DETECT_RANGE);
 
-        // detected range auras
-        RetDistance += player->GetTotalAuraModifier(SPELL_AURA_MOD_DETECTED_RANGE);
+        aggroRadius += GetTotalAuraModifier(SPELL_AURA_MOD_DETECTED_RANGE);
     }
 
-    // "Minimum Aggro Radius for a mob seems to be combat range (5 yards)"
-    if (RetDistance < 5)
-        RetDistance = 5;
+    // The aggro range of creatures with higher levels than the total player level for the expansion should get the maxlevel treatment
+    // This makes sure that creatures such as bosses wont have a bigger aggro range than the rest of the npc's
+    // The following code is used for blizzlike behaivior such as skipable bosses (e.g. Commander Springvale at level 85)
+    if (getLevel() > expansionMaxLevel)
+        aggroRadius = baseAggroDistance + float(expansionMaxLevel - player->getLevel());
 
-    return (RetDistance*aggroRate);
+    // Make sure that we wont go over the total range limits
+    if (aggroRadius > maxRadius)
+        aggroRadius = maxRadius;
+    else if (aggroRadius < minRadius)
+        aggroRadius = minRadius;
+
+    return (aggroRadius * aggroRate);
 }
 
 void Creature::setDeathState(DeathState s)

src/server/game/Handlers/ReferAFriendHandler.cpp

@@ -22,30 +22,6 @@
 #include "ReferAFriendPackets.h"
 #include "World.h"
 
-inline uint32 GetMaxLevelForExpansion(uint32 expansion)
-{
-    switch (expansion)
-    {
-        case EXPANSION_CLASSIC:
-            return 60;
-        case EXPANSION_THE_BURNING_CRUSADE:
-            return 70;
-        case EXPANSION_WRATH_OF_THE_LICH_KING:
-            return 80;
-        case EXPANSION_CATACLYSM:
-            return 85;
-        case EXPANSION_MISTS_OF_PANDARIA:
-            return 90;
-        case EXPANSION_WARLORDS_OF_DRAENOR:
-            return 100;
-        case EXPANSION_LEGION:
-            return 110;
-        default:
-            break;
-    }
-    return 0;
-}
-
 void WorldSession::HandleGrantLevel(WorldPackets::RaF::GrantLevel& grantLevel)
 {
     Player* target = ObjectAccessor::GetPlayer(*_player, grantLevel.Target);

src/server/game/Miscellaneous/SharedDefines.h

@@ -90,6 +90,30 @@ enum Expansions
 
 #define CURRENT_EXPANSION EXPANSION_LEGION
 
+inline uint32 GetMaxLevelForExpansion(uint32 expansion)
+{
+    switch (expansion)
+    {
+        case EXPANSION_CLASSIC:
+            return 60;
+        case EXPANSION_THE_BURNING_CRUSADE:
+            return 70;
+        case EXPANSION_WRATH_OF_THE_LICH_KING:
+            return 80;
+        case EXPANSION_CATACLYSM:
+            return 85;
+        case EXPANSION_MISTS_OF_PANDARIA:
+            return 90;
+        case EXPANSION_WARLORDS_OF_DRAENOR:
+            return 100;
+        case EXPANSION_LEGION:
+            return 110;
+        default:
+            break;
+    }
+    return 0;
+}
+
 enum Gender
 {
     GENDER_UNKNOWN                     = -1,