DB/Creature: Add a new extra_flag CREATURE_FLAG_EXTRA_NO_PLAYER_DAMAGE_REQ (0x00200000) that awards players credit for killing the creature even if less than 50% of damage was dealt by players.

This can be used to fix quests such as "Heated Battle" or "If Valgarde Falls..." that are currently very hard to complete at the appropriate level due to "friendly" NPCs killing off the required targets too quickly for players to get 50% of damage in.

(cherry picked from commit d240ccb38c05e394b181a09d42f5e55d3222603a)

4 files changed, 32 insertions, 21 deletions

diff --git a/sql/updates/world/2016_01_13_playerdamagereq.sql b/sql/updates/world/2016_01_13_playerdamagereq.sql
new file mode 100644
index 00000000000..ce561af3a61
--- /dev/null
+++ b/sql/updates/world/2016_01_13_playerdamagereq.sql
@@ -0,0 +1,5 @@
+-- Transition some creatures to use new CREATURE_FLAGS_EXTRA_NO_PLAYER_DAMAGE_REQ
+-- 27685/27686/27531: Target creatures for Quest 12416 ("Heated Battle")
+-- 24051/24063: Target creatures for Quest 11243 ("If Valgarde Falls...")
+-- 28034/28035/28036: Targets for Quest 12508 ("Mopping Up")
+UPDATE `creature_template` SET `flags_extra`=(`flags_extra`|2097152) WHERE `entry` IN (27685,27686,27531,24051,24063,28034,28035,28036);
diff --git a/src/server/game/Entities/Creature/Creature.h b/src/server/game/Entities/Creature/Creature.h
index 73183b6f8dd..54e472a56d3 100644
--- a/src/server/game/Entities/Creature/Creature.h
+++ b/src/server/game/Entities/Creature/Creature.h
@@ -39,23 +39,24 @@ class WorldSession;
 
 enum CreatureFlagsExtra
 {
-    CREATURE_FLAG_EXTRA_INSTANCE_BIND       = 0x00000001,       // creature kill bind instance with killer and killer's group
-    CREATURE_FLAG_EXTRA_CIVILIAN            = 0x00000002,       // not aggro (ignore faction/reputation hostility)
-    CREATURE_FLAG_EXTRA_NO_PARRY            = 0x00000004,       // creature can't parry
-    CREATURE_FLAG_EXTRA_NO_PARRY_HASTEN     = 0x00000008,       // creature can't counter-attack at parry
-    CREATURE_FLAG_EXTRA_NO_BLOCK            = 0x00000010,       // creature can't block
-    CREATURE_FLAG_EXTRA_NO_CRUSH            = 0x00000020,       // creature can't do crush attacks
-    CREATURE_FLAG_EXTRA_NO_XP_AT_KILL       = 0x00000040,       // creature kill not provide XP
-    CREATURE_FLAG_EXTRA_TRIGGER             = 0x00000080,       // trigger creature
-    CREATURE_FLAG_EXTRA_NO_TAUNT            = 0x00000100,       // creature is immune to taunt auras and effect attack me
-    CREATURE_FLAG_EXTRA_WORLDEVENT          = 0x00004000,       // custom flag for world event creatures (left room for merging)
-    CREATURE_FLAG_EXTRA_GUARD               = 0x00008000,       // Creature is guard
-    CREATURE_FLAG_EXTRA_NO_CRIT             = 0x00020000,       // creature can't do critical strikes
-    CREATURE_FLAG_EXTRA_NO_SKILLGAIN        = 0x00040000,       // creature won't increase weapon skills
-    CREATURE_FLAG_EXTRA_TAUNT_DIMINISH      = 0x00080000,       // Taunt is a subject to diminishing returns on this creautre
-    CREATURE_FLAG_EXTRA_ALL_DIMINISH        = 0x00100000,       // Creature is subject to all diminishing returns as player are
-    CREATURE_FLAG_EXTRA_DUNGEON_BOSS        = 0x10000000,       // creature is a dungeon boss (SET DYNAMICALLY, DO NOT ADD IN DB)
-    CREATURE_FLAG_EXTRA_IGNORE_PATHFINDING  = 0x20000000        // creature ignore pathfinding
+    CREATURE_FLAG_EXTRA_INSTANCE_BIND        = 0x00000001,       // creature kill bind instance with killer and killer's group
+    CREATURE_FLAG_EXTRA_CIVILIAN             = 0x00000002,       // not aggro (ignore faction/reputation hostility)
+    CREATURE_FLAG_EXTRA_NO_PARRY             = 0x00000004,       // creature can't parry
+    CREATURE_FLAG_EXTRA_NO_PARRY_HASTEN      = 0x00000008,       // creature can't counter-attack at parry
+    CREATURE_FLAG_EXTRA_NO_BLOCK             = 0x00000010,       // creature can't block
+    CREATURE_FLAG_EXTRA_NO_CRUSH             = 0x00000020,       // creature can't do crush attacks
+    CREATURE_FLAG_EXTRA_NO_XP_AT_KILL        = 0x00000040,       // creature kill not provide XP
+    CREATURE_FLAG_EXTRA_TRIGGER              = 0x00000080,       // trigger creature
+    CREATURE_FLAG_EXTRA_NO_TAUNT             = 0x00000100,       // creature is immune to taunt auras and effect attack me
+    CREATURE_FLAG_EXTRA_WORLDEVENT           = 0x00004000,       // custom flag for world event creatures (left room for merging)
+    CREATURE_FLAG_EXTRA_GUARD                = 0x00008000,       // Creature is guard
+    CREATURE_FLAG_EXTRA_NO_CRIT              = 0x00020000,       // creature can't do critical strikes
+    CREATURE_FLAG_EXTRA_NO_SKILLGAIN         = 0x00040000,       // creature won't increase weapon skills
+    CREATURE_FLAG_EXTRA_TAUNT_DIMINISH       = 0x00080000,       // Taunt is a subject to diminishing returns on this creautre
+    CREATURE_FLAG_EXTRA_ALL_DIMINISH         = 0x00100000,       // creature is subject to all diminishing returns as player are
+    CREATURE_FLAG_EXTRA_NO_PLAYER_DAMAGE_REQ = 0x00200000,       // creature does not need to take player damage for kill credit
+    CREATURE_FLAG_EXTRA_DUNGEON_BOSS         = 0x10000000,       // creature is a dungeon boss (SET DYNAMICALLY, DO NOT ADD IN DB)
+    CREATURE_FLAG_EXTRA_IGNORE_PATHFINDING   = 0x20000000        // creature ignore pathfinding
 };
 
 #define CREATURE_FLAG_EXTRA_DB_ALLOWED (CREATURE_FLAG_EXTRA_INSTANCE_BIND | CREATURE_FLAG_EXTRA_CIVILIAN | \
@@ -63,7 +64,7 @@ enum CreatureFlagsExtra
     CREATURE_FLAG_EXTRA_NO_CRUSH | CREATURE_FLAG_EXTRA_NO_XP_AT_KILL | CREATURE_FLAG_EXTRA_TRIGGER | \
     CREATURE_FLAG_EXTRA_NO_TAUNT | CREATURE_FLAG_EXTRA_WORLDEVENT | CREATURE_FLAG_EXTRA_NO_CRIT | \
     CREATURE_FLAG_EXTRA_NO_SKILLGAIN | CREATURE_FLAG_EXTRA_TAUNT_DIMINISH | CREATURE_FLAG_EXTRA_ALL_DIMINISH | \
-    CREATURE_FLAG_EXTRA_GUARD | CREATURE_FLAG_EXTRA_IGNORE_PATHFINDING)
+    CREATURE_FLAG_EXTRA_GUARD | CREATURE_FLAG_EXTRA_IGNORE_PATHFINDING | CREATURE_FLAG_EXTRA_NO_PLAYER_DAMAGE_REQ)
 
 #define CREATURE_REGEN_INTERVAL 2 * IN_MILLISECONDS
 
@@ -689,7 +690,7 @@ class TC_GAME_API Creature : public Unit, public GridObject<Creature>, public Ma
 
         void SetDisableReputationGain(bool disable) { DisableReputationGain = disable; }
         bool IsReputationGainDisabled() const { return DisableReputationGain; }
-        bool IsDamageEnoughForLootingAndReward() const { return m_PlayerDamageReq == 0; }
+        bool IsDamageEnoughForLootingAndReward() const { return (m_creatureInfo->flags_extra & CREATURE_FLAG_EXTRA_NO_PLAYER_DAMAGE_REQ) || (m_PlayerDamageReq == 0); }
         void LowerPlayerDamageReq(uint32 unDamage);
         void ResetPlayerDamageReq() { m_PlayerDamageReq = GetHealth() / 2; }
         uint32 m_PlayerDamageReq;
diff --git a/src/server/game/Miscellaneous/Formulas.h b/src/server/game/Miscellaneous/Formulas.h
index 1b9d36c25cf..9d1e237ff74 100644
--- a/src/server/game/Miscellaneous/Formulas.h
+++ b/src/server/game/Miscellaneous/Formulas.h
@@ -181,6 +181,9 @@ namespace Trinity
                 }
 
                 xpMod *= isBattleGround ? sWorld->getRate(RATE_XP_BG_KILL) : sWorld->getRate(RATE_XP_KILL);
+                if (creature->m_PlayerDamageReq) // if players dealt less than 50% of the damage and were credited anyway (due to CREATURE_FLAG_EXTRA_NO_PLAYER_DAMAGE_REQ), scale XP gained appropriately (linear scaling)
+                    xpMod *= 1.0f - 2.0f*creature->m_PlayerDamageReq / creature->GetMaxHealth();
+
                 gain = uint32(gain * xpMod);
             }
 
diff --git a/src/server/scripts/Commands/cs_npc.cpp b/src/server/scripts/Commands/cs_npc.cpp
index eff027904e5..8eba6e5a02d 100644
--- a/src/server/scripts/Commands/cs_npc.cpp
+++ b/src/server/scripts/Commands/cs_npc.cpp
@@ -43,7 +43,7 @@ struct EnumName
 #define CREATE_NAMED_ENUM(VALUE) { VALUE, STRINGIZE(VALUE) }
 
 #define NPCFLAG_COUNT   24
-#define FLAGS_EXTRA_COUNT 16
+#define FLAGS_EXTRA_COUNT 18
 
 EnumName<NPCFlags, int32> const npcFlagTexts[NPCFLAG_COUNT] =
 {
@@ -163,7 +163,9 @@ EnumName<CreatureFlagsExtra> const flagsExtra[FLAGS_EXTRA_COUNT] =
     CREATE_NAMED_ENUM(CREATURE_FLAG_EXTRA_NO_SKILLGAIN),
     CREATE_NAMED_ENUM(CREATURE_FLAG_EXTRA_TAUNT_DIMINISH),
     CREATE_NAMED_ENUM(CREATURE_FLAG_EXTRA_ALL_DIMINISH),
-    CREATE_NAMED_ENUM(CREATURE_FLAG_EXTRA_DUNGEON_BOSS)
+    CREATE_NAMED_ENUM(CREATURE_FLAG_EXTRA_NO_PLAYER_DAMAGE_REQ),
+    CREATE_NAMED_ENUM(CREATURE_FLAG_EXTRA_DUNGEON_BOSS),
+    CREATE_NAMED_ENUM(CREATURE_FLAG_EXTRA_IGNORE_PATHFINDING)
 };
 
 class npc_commandscript : public CommandScript