Add cvar to prevent zombies from flinching during actbusies and scripted sequences

sp/src/game/server/hl2/npc_BaseZombie.cpp

@@ -159,6 +159,10 @@ ConVar zombie_decaymax( "zombie_decaymax", "0.4" );
 
 ConVar zombie_ambushdist( "zombie_ambushdist", "16000" );
 
+#ifdef MAPBASE
+ConVar	zombie_no_flinch_during_unique_anim( "zombie_no_flinch_during_unique_anim", "1", FCVAR_NONE, "Prevents zombies from flinching during actbusies and scripted sequences." );
+#endif
+
 //=========================================================
 // For a couple of reasons, we keep a running count of how
 // many zombies in the world are angry at any given time.
@@ -1927,6 +1931,31 @@ void CNPC_BaseZombie::OnScheduleChange( void )
 }
 
 
+//---------------------------------------------------------
+//---------------------------------------------------------
+
+bool CNPC_BaseZombie::CanFlinch( void )
+{
+	if (!BaseClass::CanFlinch())
+		return false;
+
+#ifdef MAPBASE
+	if (zombie_no_flinch_during_unique_anim.GetBool())
+	{
+		// Don't flinch if currently playing actbusy animation (navigating to or from one is fine)
+		if (m_ActBusyBehavior.IsInsideActBusy())
+			return false;
+
+		// Don't flinch if currently playing scripted sequence (navigating to or from one is fine)
+		if (m_NPCState == NPC_STATE_SCRIPT && (IsCurSchedule( SCHED_SCRIPTED_WAIT, false ) || IsCurSchedule( SCHED_SCRIPTED_FACE, false )))
+			return false;
+	}
+#endif
+
+	return true;
+}
+
+
 //---------------------------------------------------------
 //---------------------------------------------------------
 int	CNPC_BaseZombie::SelectFailSchedule( int failedSchedule, int failedTask, AI_TaskFailureCode_t taskFailCode )

sp/src/game/server/hl2/npc_BaseZombie.h

@@ -151,6 +151,8 @@ public:
 	int OnTakeDamage_Alive( const CTakeDamageInfo &info );
 	virtual float	GetReactionDelay( CBaseEntity *pEnemy ) { return 0.0; }
 
+	bool CanFlinch( void );
+
 	virtual int SelectSchedule ( void );
 	virtual int	SelectFailSchedule( int failedSchedule, int failedTask, AI_TaskFailureCode_t taskFailCode );
 	virtual void BuildScheduleTestBits( void );