Overview

Dynamic covers, generated offline and adjusted during run time

Example: CoverSurface and HMMWV

(Here ai_DebugDraw=1, ai_DebugDrawCover=2, and [AI/Physics] is on.)

Dynamic tactical points

Example: A very shy civilian who always wants to hide from the player

• TPS query:

  AI.RegisterTacticalPointQuery({
    Name = "Civilian_HideFromEnemy",
    {
      Generation =
      {
        cover_from_attentionTarget_around_puppet = 25
      },
      Conditions =
      {
        reachable = true,
      },
      Weights =
      {
        distance_from_puppet = -1,
      },
    },
  });

• TPS query referenced in a goalpipe:

  <GoalPipes>
    <GoalPipe name="Civilian_HideFromEnemy">
      <TacticalPos name="Civilian_HideFromEnemy"/>
    </GoalPipe>
  </GoalPipes>

• Goalpipe selected in a behavior:

  local Behavior = CreateAIBehavior("CivilianIdle",
  {
    Alertness = 0,
    
    OnEnemySeen = function(self, entity, distance)
      entity:SelectPipe(0, "Civilian_HideFromEnemy");
    end,
    
    OnTPSDestReached = function(self, entity)
      entity:SelectPipe(0, "_first_");
    end,
  })

• Grunt's properties:

• Useful AI debug draw:
  • ai_DebugTacticalPoints=1
  • ai_StatsTarget=Grunt1
  • ai_TacticalPointsDebugTime=10

• For more realism, add the following before goalop TacticalPos:

  <Speed id="Sprint"/>

Behavior trees

Example: A civilian who hides from the shooting player

• New Civilian behavior:

  <?xml version="1.0" encoding="utf-8"?>
  
  <SelectionTrees>
    <SelectionTree name="Civilian" type="BehaviorSelectionTree">
    
      <Variables>
        <Variable name="alerted"/>
      </Variables>
    
      <SignalVariables>
        <Signal name="OnNoTarget" variable="alerted" value="false"/>
      </SignalVariables>
      
      <LeafTranslations>
        <Map node="Alerted" target="CivilianAlerted"/>
        <Map node="Idle" target="CivilianIdle"/>
      </LeafTranslations>
      
      <Priority name="Root">
        <Leaf name="Alerted" condition="alerted"/>
        <Leaf name="Idle"/>
      </Priority>
      
    </SelectionTree>
  </SelectionTrees>

• Idle behavior:

  local Behavior = CreateAIBehavior("CivilianIdle",
  {
    Alertness = 0,
    
    OnBulletRain = function(self, entity, sender, data)
      entity.AI.hostileId = data.id;
      AI.AddPersonallyHostile(entity.id, entity.AI.hostileId);
      AI.SetBehaviorVariable(entity.id, "alerted", true);
    end,
    
    OnTPSDestReached = function(self, entity)  
      entity:SelectPipe(0, "_first_");  
    end,  
  });

• Alerted behavior:

  local Behavior = CreateAIBehavior("CivilianAlerted", "CivilianIdle",
  {
    Alertness = 2,
  
    Constructor = function(self, entity)
      entity:SelectPipe(0, "Civilian_HideFromEnemy");  
    end,
    
    Destructor = function(self, entity)
      AI.RemovePersonallyHostile(entity.id, entity.AI.hostileId);
    end,
  });

• Civilian's properties:

• Useful AI debug draw:
  • ai_DebugTargetTracksAgent=Grunt1

• Check out Views:
  • AI Debugger
  • Behavior Selection Tree Editor