From dfcd41abefec371e6af9db7db92c1dd55aa701ff Mon Sep 17 00:00:00 2001
From: Shauren <shauren.trinity@gmail.com>
Date: Fri, 28 Mar 2025 23:42:39 +0100
Subject: Core/Spells: Apply spell modifiers multiple times to each cast, based
 on number of matched SpellFamilyFlags bits

---
 src/server/game/Spells/SpellInfo.cpp | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

(limited to 'src/server/game/Spells/SpellInfo.cpp')

diff --git a/src/server/game/Spells/SpellInfo.cpp b/src/server/game/Spells/SpellInfo.cpp
index 5cadd602089..95432f8f02c 100644
--- a/src/server/game/Spells/SpellInfo.cpp
+++ b/src/server/game/Spells/SpellInfo.cpp
@@ -37,6 +37,7 @@
 #include "SpellMgr.h"
 #include "Vehicle.h"
 #include <G3D/g3dmath.h>
+#include <bit>
 
 uint32 GetTargetFlagMask(SpellTargetObjectTypes objType)
 {
@@ -1892,11 +1893,8 @@ bool SpellInfo::IsAffectedBySpellMods() const
     return !HasAttribute(SPELL_ATTR3_IGNORE_CASTER_MODIFIERS);
 }
 
-bool SpellInfo::IsAffectedBySpellMod(SpellModifier const* mod) const
+uint32 SpellInfo::IsAffectedBySpellMod(SpellModifier const* mod) const
 {
-    if (!IsAffectedBySpellMods())
-        return false;
-
     SpellInfo const* affectSpell = sSpellMgr->GetSpellInfo(mod->spellId, Difficulty);
     if (!affectSpell)
         return false;
@@ -1905,13 +1903,21 @@ bool SpellInfo::IsAffectedBySpellMod(SpellModifier const* mod) const
     {
         case SPELLMOD_FLAT:
         case SPELLMOD_PCT:
+        {
             // TEMP: dont use IsAffected - !familyName and !familyFlags are not valid options for spell mods
             // TODO: investigate if the !familyName and !familyFlags conditions are even valid for all other (nonmod) uses of SpellInfo::IsAffected
-            return affectSpell->SpellFamilyName == SpellFamilyName && static_cast<SpellModifierByClassMask const*>(mod)->mask & SpellFamilyFlags;
+            if (affectSpell->SpellFamilyName != SpellFamilyName)
+                return false;
+
+            // spell modifiers should apply as many times as number of matched SpellFamilyFlags bits (verified with spell 1218116 with modifier 384451 in patch 11.1.0 and client tooltip code since at least 3.3.5)
+            // unknown if this is a bug or strange design choice...
+            FlagsArray<uint32, 4> matched = static_cast<SpellModifierByClassMask const*>(mod)->mask & SpellFamilyFlags;
+            return std::popcount(matched[0]) + std::popcount(matched[1]) + std::popcount(matched[2]) + std::popcount(matched[3]);
+        }
         case SPELLMOD_LABEL_FLAT:
-            return HasLabel(static_cast<SpellFlatModifierByLabel const*>(mod)->value.LabelID);
+            return HasLabel(static_cast<SpellFlatModifierByLabel const*>(mod)->value.LabelID) ? 1 : 0;
         case SPELLMOD_LABEL_PCT:
-            return HasLabel(static_cast<SpellPctModifierByLabel const*>(mod)->value.LabelID);
+            return HasLabel(static_cast<SpellPctModifierByLabel const*>(mod)->value.LabelID) ? 1 : 0;
         default:
             break;
     }
@@ -5013,5 +5019,5 @@ bool SpellInfo::MeetsFutureSpellPlayerCondition(Player const* player) const
 
 bool SpellInfo::HasLabel(uint32 labelId) const
 {
-    return Labels.find(labelId) != Labels.end();
+    return Labels.contains(labelId);
 }
-- 
cgit v1.2.3