View source for AI behaviour depending on player actions

  Attention: This approach is outdated. For a newer one see [http://wiki.thedarkmod.com/index.php?title=AI_behaviour_depending_on_players_actions_%28new_version%29 here]

I am going to describe the setup of a mission, in which the AI is neutral to the player as default. The AI only gets hostile to the player, if the player is seen performing an illegal action. Such actions include: Being seen in an area where the player isn't supposed to be, stealing loot, or carrying a weapon.

The first thing you have to do is to put all affected AI on one team. Let's just take team 1. So set the spawnarg "team" "1" on all affected AI and make sure non-affected AI are on a different team. Create a ''target_setrelation'' entity and set the following spawnarg on it: "rel 1,0" "0". This will cause the AI on team 1 to see the player (team 0) as neutral (0). Target this entity from a worldspawn brush or trigger it via the command

  sys.trigger($nameof_target_setrelation);

included in your main() script function.

== Being seen in an area where you aren't supposed to be ==

The first thing you need to do is to make use of the zone system. This approach is described [http://wiki.thedarkmod.com/index.php?title=Ambient_Sounds,_a_zone_approach, here]. This system allows you to call functions when the player passes from one zone to another. Here we'll make use of the ''call_on_entry'' script function. The following has to be applied to all allowed/disallowed zones neighboring each other. On the ''info_location'' entities belonging to the zones set the spawnarg "call_on_entry" "''functionname''", where ''functionname'' is:

''setNeutralZone'' on allowed zones
''setHostileZone'' on disallowed zones

The functions used here have to have the form '''void''' ''functionname''('''entity''' ''entityname''). The ''entity'' is the zone the player enters. As we don't need it here, but need the basic behavior for the weapon-based AI-player relation discussed below, they just call other functions with the same names without ''Zone'' at the end and no arguments passed. What they do is trigger the ''target_setrelation'' entities from the next section named ... 

== Caught stealing ==

This makes use of some triggers. You'll need two ''target_setrelation'' entities and one ''trigger_relay'' entity.

On the first ''target_setrelation'' entity set the spawnarg "rel 1,0" "-1". On the second, set "rel 1,0" "0". Let the ''trigger_relay'' target the second ''target_setrelation'' entity and set the spawnarg "delay" "T" on the ''trigger_relay'', where T specifies the timespan in which the player is detected as hostile after stealing something (see description below).

Now let '''every''' item that the player is not allowed to take target both the first ''target_setrelation'' and the ''trigger_relay'' entity. The next thing you need to do is to set up a hidden objective with the content "If one AI of team 1 goes to alert state 5". In the '''success script''' field enter ''isHostile''. This function will then destroy the second ''target_setrelation'' entity, so the AI stays hostile to the player.

''Note: alert state 5 is the highest alert state and means that the player was seen by an AI.''

What does the setup do?

Every time you steal something the AI from team 1 will be set hostile to you for a certain amount of time. After that period they will become neutral to you again, unless they see you within this amount of time. If so, they'll stay hostile. As you can see the amount of time (called T above) has an impact on how difficult it is for the player to get away with disallowed actions. Setting it to a higher value makes it more difficult and vice versa.

== Being seen carrying a weapon ==

You'll need the following script:

  void CheckWeapon()
  {
        do
        {
              if ($player1.getCurrentWeapon() != "atdm:weapon_unarmed") {
                    setHostile_();
                    sys.wait(1);
                    if (!hostile) setNeutral_();       
              } 
              else {
                    sys.wait(1);
              }
        } while(true); 
  }

This function is started from the ''main'' method via 

  thread CheckWeapon();

The functions ''setNeutral_'' and ''setHostile_'' are almost the same as above. For the differences see below. The script sets the AI to hostile as long as you carry a weapon. Again, being seen by any hostile AI will cause the hostility to be permanent.

== Caught lockpicking ==

If we want the player to be threated as an enemy when caught while lockpicking, we just need to add the following lines of code into the ''checkWeapon'' function:

        t=$player1.getFrobbed();
        if(t!=$null) {
          if (t.IsLocked()) {
            classname = $player1.getCurInvItemEntity().getKey("classname");
            if ( classname == snake || classname == triangle) {
              if (t.GetDoorhandle().isRotating()) {
                setHostile_();
                sys.wait(1.0);
                if(!hostile) setNeutral_();
              } //endif rotate
            } //endif lockpick
          }//endif locked
        }//endif null
        else { 
          sys.wait(1.0);
        }

== Beeing seen flashing an AI ==

If an AI is seeing you flashing another AI (but don't get flashed itself), you can be pretty sure he will engage you unless he really dislikes the flashed comrade. To achieve this add the following response via the stim/response menu to every AI. The stim type must be '''flash''' and the response is '''Run script'''. The script is named ''flashed'' and is as follows

  void flashed() {
    setHostile();
    sys.wait(3.0);
    setNetral();
  }

== Beeing seen carrying a body ==

The last thing we want to add is that the AI reacts to the player when carrying an unconscious or dead body. The following script lines will also be added to the ''checkWeapon'' method and will make AI hostile if the player frobs an AI. 

  if ($player1.heldEntity()!=$null) {
        if ($player1.heldEntity().getKey("spawnclass")=="idAI") {
          setHostile_();
          sys.wait(1.0);
          if(!hostile) setNeutral_();       
        }
  }

This method checks wether the player holds something in his hands and, if so, if it is an AI. The method will not identify the player as hostile when he has shouldered an AI. For this purpose we need to add the following two spawnargs on every AI: "equip_action_script" "setHostile" and "dequip_action_script" "setNeutral".


== Summary ==

Now that we have all the pieces together, let's sum up how to set up the complete behavior. (We are starting from zero here; nothing has been done so far).

We need:

Two ''target_setrelation'' entities called '''makeHostile''' and '''makeNeutral'''

One ''trigger_relay'' entity called '''relay'''

A script file called ''mymapname''.script, where ''mymapname'' is the name of your map.

An invisible objective "If one AI of team 1 get to alert level 5".

----

On all affected AI set "team" "1". Non-affected AI go to another team.

Also set the spawnargs "equip_action_script" "setHostile" and "dequip_action_script" "setNeutral" on them.

Give them a response to flash that runs the script ''flashed()''

On '''makeHostile''' set "rel 1,0" "-1".

On '''makeNeutral''' set "rel 1,0" "0".

On '''relay''' set "target" "makeNeutral" and "delay" "1".

On the objective put ''stayHostile'' in the '''success script''' field.

On '''all''' objects that are not allowed to be taken by the player set "target" "makeHostile" and "target0" "relay".

Do the same with doors that are not allowed to be opened by the player.

On '''all''' ''info_location'' entities belonging to zones where the player is not allowed to be, set "call_on_entry" "setHostileZone".

Do the same for '''all''' other ''info_location'' entities but use the method "setNeutralZone".

''Hint: The last two steps can be restricted to zones neighboring zones of the other kind''.

On '''any''' worldspawn set "target" "makeNeutral" or add the line "sys.trigger($makeNeutral);" at the first line of your ''main'' method

----

In the script file include

  float hostile=0;
  void setHostile() {
    sys.trigger($makeHostile);
    hostile=1;
  }
  void setNeutral() {
    sys.trigger($makeNeutral);
    hostile=0;
  }
  void setHostile_() {
    sys.trigger($makeHostile);
  }
  void setNeutral_() {
    sys.trigger($makeNeutral);
  }
  void setHostileZone(entity zone) {
    setHostile();
  }
  void setNeutralZone(entity zone) {
    setNeutral();
  }
  void stayHostile() {
    setHostile();
    $makeNeutral.remove();
  }
  void flashed() {
    setHostile();
    sys.wait(3.0);
    setNeutral();
  }
  void CheckWeapon() {
    entity t;
    string classname,snake,triangle;
    snake="atdm:playertools_lockpick_snake";
    triangle="atdm:playertools_lockpick_triangle";
    do {
      if(!hostile) {
        if ($player1.getCurrentWeapon() != "atdm:weapon_unarmed") {
          setHostile_();
          sys.wait(1.0);
          if(!hostile) setNeutral_();       
        } //endif weapon
        else if ($player1.heldEntity()!=$null) {
          if ($player1.heldEntity().getKey("spawnclass")=="idAI") {
            setHostile_();
            sys.wait(1.0);
            if(!hostile) setNeutral_();       
          }
        } //endif held
        else  {
          t=$player1.getFrobbed();
          if(t!=$null) {
            if (t.IsLocked()) {
              classname = $player1.getCurInvItemEntity().getKey("classname");
              if ( classname == snake || classname == triangle) {
                if (t.GetDoorhandle().isRotating()) {
                  setHostile_();
                  sys.wait(1.0);
                  if(!hostile) setNeutral_();
                } //endif rotate
              } //endif lockpick
            }//endif locked
          }//endif null
          else { 
            sys.wait(1.0);
          }
        }
      }//endif hostile
      else {
        sys.wait(1.0);
      }
      sys.wait(0.1);
    } while(true);
  }
  void main() {
    setNeutral();
    thread CheckWeapon();
  } 

That's it. If you want to make the detection time for stealing things difficulty-dependent, add the following spawnargs on '''relay''':

"diff_1_change_0" "delay"
"diff_1_arg_0" "1.5"
"diff_2_change_0" "delay"
"diff_2_arg_0" "2.0"

Also, you could replace the times in the code by a variable that is set depending on the choosen difficulty. There is no need to choose the time for flashing higher then for the other hostilities, but it seemed more senseful to me while testing. Of course, you can use other times than mentioned here. The best idea is maybe to test this in game, as these things will hardly depend on the map layout, room sizes, patrol routes, lighting and so one.

Note, that this setup will alert the whole team at a time. So if the player is able to escape an alerted guard or is able to shut him down and hide him before support arrives, this won't be to much use for him. I had not much luck setting up such a behaviour. But what can be done is to use several teams for several areas, so the player can at least use the opportunity to escape. Obviously, this is only appropiate if the player is allowed to be identified.

== Some notes to the code ==

The first thing that may draw attention in the code is the variable ''hostile'' and the two versions of ''setHostile'' and ''setNeutral''. The problem was, that the code set the player back to neutral in some cases where he shouldn't be. If you, for example, draw your blackjack to knockout a guard, than put it away and pick up the guard, it is possible that you become neutral afterwards. What happened is, that after you drew the blackjack, the method chckweapon set you hostile in the weapon loop. While the thrad was waiting you put away your weapon and picked up the body. Now this would call the ''equip_action_script''. Then the ''checkWeapon()'' thread is ready with waiting and sets you back to neutral, although you are still carrying a body. To prevent such a behaviour, to different methods are needed here. The last ''sys.wait'' command in the do-while loop is neccessary to prevent the thread of blocking the whole cpu in some situations, where none of the other ''sys.wait'' commands was executed (Very bad programming of the script language, by the way). 

== Feedback and information ==

Any kind of suggestions and/or questions can be posted [http://forums.thedarkmod.com/topic/14394-apples-and-peaches-obsttortes-mapping-and-scripting-thread, here].

--[[User:Obsttorte|Obsttorte]] ([[User talk:Obsttorte|talk]]) 11:18, 2 January 2013 (EST)

[[Category:AI]]
[[Category:Player character]]