Core/Units: only grant 50% crit damage bonus for magical periodic effects originating from ranged attacks

supercedes #463

Author: Ovahlord

src/server/game/Entities/Unit/Unit.cpp

@@ -7003,21 +7003,29 @@ float Unit::SpellCritChanceTaken(Unit const* caster, SpellInfo const* spellInfo,
     return std::max(crit_chance, 0.0f);
 }
 
-/*static*/ uint32 Unit::SpellCriticalDamageBonus(Unit const* caster, SpellInfo const* spellProto, uint32 damage)
+/*static*/ uint32 Unit::SpellCriticalDamageBonus(Unit const* caster, SpellInfo const* spellProto, uint32 damage, bool periodicDamage /*= false*/)
 {
     // Calculate critical bonus
     int32 crit_bonus = damage;
     float crit_mod = 0.0f;
 
     switch (spellProto->DmgClass)
     {
-        case SPELL_DAMAGE_CLASS_MELEE:                      // for melee based spells is 100%
-        case SPELL_DAMAGE_CLASS_RANGED:
-            /// @todo write here full calculation for melee/ranged spells
+        // Spells which are either marked as ranged or melee damage, will deal 100% additional damage
+        case SPELL_DAMAGE_CLASS_MELEE:
             crit_bonus += damage;
             break;
+        case SPELL_DAMAGE_CLASS_RANGED:
+            // Ranged spells which have magic periodic damage effect on the other hand, only deal 50% damage, just like spells
+            // This is a very specific case that is currently only known for Hunter spells, such as Serpent Sting and Black Arrow
+            if (periodicDamage && (spellProto->GetSchoolMask() & SPELL_SCHOOL_MASK_MAGIC) != 0)
+                crit_bonus += damage / 2;
+            else
+                crit_bonus += damage;
+            break;
         default:
-            crit_bonus += damage / 2;                       // for spells is 50%
+            // Magic spells will simply deal 50% additional crit damage
+            crit_bonus += damage / 2;
             break;
     }
 

src/server/game/Entities/Unit/Unit.h

@@ -1458,7 +1458,7 @@ class TC_GAME_API Unit : public WorldObject
         bool IsBlockCritical() const;
         float SpellCritChanceDone(SpellInfo const* spellInfo, SpellSchoolMask schoolMask, WeaponAttackType attackType = BASE_ATTACK, bool isPeriodic = false) const;
         float SpellCritChanceTaken(Unit const* caster, SpellInfo const* spellInfo, SpellSchoolMask schoolMask, float doneChance, WeaponAttackType attackType = BASE_ATTACK, bool isPeriodic = false) const;
-        static uint32 SpellCriticalDamageBonus(Unit const* caster, SpellInfo const* spellProto, uint32 damage);
+        static uint32 SpellCriticalDamageBonus(Unit const* caster, SpellInfo const* spellProto, uint32 damage, bool periodicDamage = false);
         static uint32 SpellCriticalHealingBonus(Unit const* caster, uint32 damage);
 
         uint32 GetCastingTimeForBonus(SpellInfo const* spellProto, DamageEffectType damagetype, uint32 CastingTime) const;

src/server/game/Spells/Auras/SpellAuraEffects.cpp

@@ -5839,7 +5839,7 @@ void AuraEffect::HandlePeriodicDamageAurasTick(Unit* target, Unit* caster) const
         crit = roll_chance_f(GetCritChanceFor(caster, target));
 
     if (crit)
-        damage = Unit::SpellCriticalDamageBonus(caster, m_spellInfo, damage);
+        damage = Unit::SpellCriticalDamageBonus(caster, m_spellInfo, damage, true);
 
     uint32 unmitigatedDamage = damage;
 
@@ -5928,7 +5928,7 @@ void AuraEffect::HandlePeriodicHealthLeechAuraTick(Unit* target, Unit* caster) c
         crit = roll_chance_f(GetCritChanceFor(caster, target));
 
     if (crit)
-        damage = Unit::SpellCriticalDamageBonus(caster, m_spellInfo, damage);
+        damage = Unit::SpellCriticalDamageBonus(caster, m_spellInfo, damage, true);
 
     uint32 unmitigatedDamage = damage;