Fix ai_enemy_memory_fixes issues in npc_combine_s and npc_strider

Author: Blixibon

sp/src/game/server/ai_basenpc_schedule.cpp

@@ -46,7 +46,7 @@ extern ConVar ai_use_think_optimizations;
 ConVar	ai_simulate_task_overtime( "ai_simulate_task_overtime", "0" );
 
 #ifdef MAPBASE
-ConVar	ai_enemy_memory_fixes( "ai_enemy_memory_fixes", "1", FCVAR_NONE, "Toggles Mapbase fixes for certain NPC AI not using enemy memory when it should." );
+ConVar	ai_enemy_memory_fixes( "ai_enemy_memory_fixes", "0", FCVAR_NONE, "Toggles Mapbase fixes for certain NPC AI not using enemy memory when it should." );
 #endif
 
 #define MAX_TASKS_RUN 10

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

@@ -2551,6 +2551,24 @@ int CNPC_Combine::TranslateSchedule( int scheduleType )
 				}
 			}
 
+#ifdef MAPBASE
+			extern ConVar ai_enemy_memory_fixes;
+
+			// SCHED_COMBINE_ESTABLISH_LINE_OF_FIRE uses TASK_GET_PATH_TO_ENEMY_LKP_LOS, a task with a mistake
+			// detailed in CAI_BaseNPC::StartTask and fixed by ai_enemy_memory_fixes.
+			// 
+			// However, SCHED_COMBINE_ESTABLISH_LINE_OF_FIRE only stops being used once the NPC has LOS to its target.
+			// Since the fixed task now uses the enemy's last known position instead of the enemy's actual position,
+			// this schedule risks getting stuck in a loop.
+			// 
+			// This code makes the soldier run up directly to the last known position if it's visible, allowing the AI
+			// to mark the enemy as eluded.
+			if ( ai_enemy_memory_fixes.GetBool() && FVisible( GetEnemyLKP() ) )
+			{
+				return SCHED_COMBINE_PRESS_ATTACK;
+			}
+#endif
+
 			return SCHED_COMBINE_ESTABLISH_LINE_OF_FIRE;
 		}
 		break;

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

@@ -69,6 +69,7 @@ class CNPC_Combine : public CAI_BaseActor
 	int				RangeAttack2Conditions( float flDot, float flDist ); // For innate grenade attack
 	int				MeleeAttack1Conditions( float flDot, float flDist ); // For kick/punch
 	bool			FVisible( CBaseEntity *pEntity, int traceMask = MASK_BLOCKLOS, CBaseEntity **ppBlocker = NULL );
+	bool			FVisible( const Vector &vecTarget, int traceMask = MASK_BLOCKLOS, CBaseEntity **ppBlocker = NULL ) { return BaseClass::FVisible( vecTarget, traceMask, ppBlocker ); }
 	virtual bool	IsCurTaskContinuousMove();
 
 	virtual float	GetJumpGravity() const		{ return 1.8f; }

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

@@ -1511,6 +1511,26 @@ int CNPC_Strider::TranslateSchedule( int scheduleType )
 				return SCHED_COMBAT_PATROL;
 			}
 		}
+		else
+		{
+#ifdef MAPBASE
+			extern ConVar ai_enemy_memory_fixes;
+
+			// Striders convert TASK_GET_PATH_TO_ENEMY_LOS to TASK_GET_PATH_TO_ENEMY_LKP_LOS, a task which incorrectly
+			// acts identically to the former. This is detailed in CAI_BaseNPC::StartTask and fixed by ai_enemy_memory_fixes.
+			// 
+			// However, SCHED_ESTABLISH_LINE_OF_FIRE only stops being used once the NPC has LOS to its target.
+			// Since the fixed task now uses the enemy's last known position instead of the enemy's actual position,
+			// this schedule risks getting stuck in a loop.
+			// 
+			// This code chains back up to SCHED_ESTABLISH_LINE_OF_FIRE_FALLBACK, which is what's supposed to happen when a
+			// strider is eluded in this way.
+			if ( ai_enemy_memory_fixes.GetBool() && FVisible( GetEnemyLKP() ) )
+			{
+				return TranslateSchedule( SCHED_ESTABLISH_LINE_OF_FIRE_FALLBACK );
+			}
+#endif
+		}
 
 		break;
 

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

@@ -188,6 +188,7 @@ class CNPC_Strider : public CAI_BlendingHost<CAI_BaseNPC>,
 	bool			HasPass()	{ return m_PlayerFreePass.HasPass(); }
 
 	bool			FVisible( CBaseEntity *pEntity, int traceMask = MASK_BLOCKLOS, CBaseEntity **ppBlocker = NULL );
+	bool			FVisible( const Vector &vecTarget, int traceMask = MASK_BLOCKLOS, CBaseEntity **ppBlocker = NULL ) { return BaseClass::FVisible( vecTarget, traceMask, ppBlocker ); }
 	Vector			BodyTarget( const Vector &posSrc, bool bNoisy );
 
 	bool			IsValidEnemy( CBaseEntity *pTarget );