Difference between revisions of "AI Perception Behavior Enhancement"

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m (Pretty sure that condition merging requires bitwise operators, if it even exists and works as intended.)
m (Syntax highlighting and some cleanup)
 
Line 3: Line 3:
 
With the modification below the NPC will investigate the source of the sound instead.
 
With the modification below the NPC will investigate the source of the sound instead.
  
Open the <code>ai_basenpc_schedule.cpp</code> file and look for the function <code>SelectAlertSchedule()</code>. Look for the following code:
+
Open the '''ai_basenpc_schedule.cpp''' file and look for the function <code>SelectAlertSchedule()</code>. Look for the following code:
 
+
<source lang=cpp>
if ( HasCondition ( COND_HEAR_DANGER ) ||
+
if ( HasCondition ( COND_HEAR_DANGER ) ||
  HasCondition ( COND_HEAR_PLAYER ) ||
+
  HasCondition ( COND_HEAR_PLAYER ) ||
  HasCondition ( COND_HEAR_WORLD  ) ||
+
  HasCondition ( COND_HEAR_WORLD  ) ||
  HasCondition ( COND_HEAR_BULLET_IMPACT ) ||
+
  HasCondition ( COND_HEAR_BULLET_IMPACT ) ||
  HasCondition ( COND_HEAR_COMBAT ) )
+
  HasCondition ( COND_HEAR_COMBAT ) )
{
+
{
return SCHED_ALERT_FACE_BESTSOUND;
+
return SCHED_ALERT_FACE_BESTSOUND;
+
}
}
+
</source>
  
 
Replace this code with:
 
Replace this code with:
 
+
<source lang=cpp highlight=7>
if ( HasCondition ( COND_HEAR_DANGER ) ||
+
if ( HasCondition( COND_HEAR_DANGER ) ||
  HasCondition ( COND_HEAR_PLAYER ) ||
+
HasCondition( COND_HEAR_PLAYER ) ||
  HasCondition ( COND_HEAR_WORLD  ) ||
+
HasCondition( COND_HEAR_WORLD  ) ||
  HasCondition ( COND_HEAR_BULLET_IMPACT ) ||
+
HasCondition( COND_HEAR_BULLET_IMPACT ) ||
  HasCondition ( COND_HEAR_COMBAT ) )
+
HasCondition( COND_HEAR_COMBAT ) )
{
+
{
+
return SCHED_INVESTIGATE_SOUND;
return SCHED_INVESTIGATE_SOUND;
+
}
}
+
</source>
  
 
Alternate Code:
 
Alternate Code:
 
+
<source lang=cpp>
if ( HasCondition ( COND_HEAR_DANGER | COND_HEAR_PLAYER | COND_HEAR_WORLD | COND_HEAR_BULLET_IMPACT | COND_HEAR_COMBAT ) )
+
if ( HasCondition( COND_HEAR_DANGER | COND_HEAR_PLAYER | COND_HEAR_WORLD | COND_HEAR_BULLET_IMPACT | COND_HEAR_COMBAT ) )
{
+
{
return SCHED_INVESTIGATE_SOUND;
+
return SCHED_INVESTIGATE_SOUND;
}
+
}
 
+
</source>
 
 
  
 
==Conclusion==
 
==Conclusion==

Latest revision as of 17:00, 12 August 2021

In Half-Life 2, if an idle NPC hears a sound but doesn't see its emitter, it will only turn in the direction of the sound for a bit before returning to its previous action.

With the modification below the NPC will investigate the source of the sound instead.

Open the ai_basenpc_schedule.cpp file and look for the function SelectAlertSchedule(). Look for the following code:

	if ( HasCondition ( COND_HEAR_DANGER ) ||
			  HasCondition ( COND_HEAR_PLAYER ) ||
			  HasCondition ( COND_HEAR_WORLD  ) ||
			  HasCondition ( COND_HEAR_BULLET_IMPACT ) ||
			  HasCondition ( COND_HEAR_COMBAT ) )
	{
		return SCHED_ALERT_FACE_BESTSOUND;
	}

Replace this code with:

	if ( HasCondition( COND_HEAR_DANGER ) ||
		HasCondition( COND_HEAR_PLAYER ) ||
		HasCondition( COND_HEAR_WORLD  ) ||
		HasCondition( COND_HEAR_BULLET_IMPACT ) ||
		HasCondition( COND_HEAR_COMBAT ) )
	{
		return SCHED_INVESTIGATE_SOUND;
	}

Alternate Code:

	if ( HasCondition( COND_HEAR_DANGER | COND_HEAR_PLAYER | COND_HEAR_WORLD | COND_HEAR_BULLET_IMPACT | COND_HEAR_COMBAT ) )
	{
		return SCHED_INVESTIGATE_SOUND;
	}

Conclusion

With this code, as soon as NPC hears sounds that meet conditions, they will investigate it.