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

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

1 files changed, 28 insertions, 24 deletions

diff --git a/src/server/game/Entities/Creature/Creature.cpp b/src/server/game/Entities/Creature/Creature.cpp
index 2686c22d0a0..eccbd596dd1 100644
--- a/src/server/game/Entities/Creature/Creature.cpp
+++ b/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());
+
+    // Make sure that we wont go over the total range limits
+    if (aggroRadius > maxRadius)
+        aggroRadius = maxRadius;
+    else if (aggroRadius < minRadius)
+        aggroRadius = minRadius;
 
-    return (RetDistance*aggroRate);
+    return (aggroRadius * aggroRate);
 }
 
 void Creature::setDeathState(DeathState s)