AI Guard Unit

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This is my second attempt at making an AI controlled character. The first was an
AIPlayer that would follow paths. This character is a guard unit. The guard will
wait at it's post (spawn point) until it sees a target. It will then attack that
target while trying to close with it.

If the target is lost the bot will wait at the last place it saw the character and
look around for a little bit, and then it will try to return to it's post.

There is a chance the bot will get stuck trying to return, but there is a simple
routine that has the bot try to move in random directions to try and clear itself
of any obstacles between it and it's post. It's not perfect.

The thinking routine is a simple state machine - which can be expanded on to give the bot more responses and actions.

As with my first ai character, I am using a simple system that allows the designer to drop
markers in the game map that will mark where the bots will start out. When the mission is loaded, the markers are detected and bots are spawned at the marker locations. The markers are then hidden from view. (The markers can be left visible to help in map editing.)

The markers for the guards can be given a dynamic variable called respawn. (Assigned to the marker during map editing.) 'Respawn' will determine whether a bot respawns or not upon death.

The bots have an attention setting. How often they scan is determined by their attention level. The bots get more sluggish (freeing up processor time) when targets are too far away. Conversely, the bot becomes incrementally more attentive as targets come within range, and further aware as targets come into sight.

When a target is found in range and in sight the bot will shoot at the target. The firing sequence is a step of scheduled calls that call for a firing cycle, a trigger down cycle, and a firing delay to control bot rate of fire.

When a bot is attacked it will attempt to sideatep and it's field of vision is temporarily increased to a 360deg field of vision - to emulate looking around to see what happened. The bot's attention level is also set to make it think at it's fastest rate when attacked.

To use the AIGuard...the following changes need to be made.

1. Back up your original game.cs, player.cs, and your current build of Torque. To install AIGuard will require a recompile, since I have created a new class cloned by copying AIPlayer.cc and AIPlayer.h and renaming all references to AIPlayer to AIGuard.
(I did this because I wanted to be able to run both my AIPatroller and AIGuards in the same maps and did not want to have any confusion between them.)

2. Add the files AIGuard.cc and AIGuard.h to your Torque project. (In my instance I saved them to my c:\Torque\engine\game directory and then added them into my project.)

3. Recompile your project and copy your new executable to the appropriate directory for your app.

4. Copy the file AIGuard.cs into your server/scripts directory.

5. Modify game.cs to add the line

exec("./aiGuard.cs");

to the function onServerCreated().

6. Also in game.cs: The section for function StartGame needs to modified the following ways:

Below the lines that read:

// Start the AIManager
new ScriptObject(AIManager) {};
MissionCleanup.add(AIManager);
AIManager.think();

add this:

AIGuard::LoadEntities();

(If you followed my previous resource you may not have any reference to AImanager. Don't fret... just look for the place in game.cs where you have

AIPlayer::LoadEntities

and put in

AIGuard::LoadEntities();

right underneath it.

7. In player.cs in the code for Armor::Damage modify the lines

// Deal with client callbacks here because we don't have this
// information in the onDamage or onDisable methods
   %client = %obj.client;
   %sourceClient = %sourceObject ? %sourceObject.client : 0;
   if (%obj.getState() $= "Dead")
      %client.onDeath(%sourceObject, %sourceClient, %damageType, %location);

to read:

// Deal with client callbacks here because we don't have this
   // information in the onDamage or onDisable methods
   %client = %obj.client;
   %sourceClient = %sourceObject ? %sourceObject.client : 0;   if (%obj.isbot == true)
   {
     %obj.attentionlevel=1;
     %obj.enhancefov(%obj);
   }
 
  if (%obj.getState() $= "Dead")
 {
     if (%obj.isbot == true)
    {
        if (%obj.respawn == true)
          {
           %obj.delaybeforerespawn(%obj.botname, %obj.markerpos, %obj.marker);
           %this.player=0;
           }
    }
   else
  {
     %client.onDeath(%sourceObject, %sourceClient, %damageType, %location);
  }
  }

*** If you followed my previous resource there should be no need to change this code.

8. Load your map - Stronghold as an example.
9. Go into the map editor. (F11) Then go into the Editor Creator (F4)
10. Under Shapes there should be a drop down called AIMarker, under that a new item called AIGuard.
11. Create a new AIGuard marker.
12. Select your marker, position it where you like and hit (F3) to modify the marker.
13. If you want to override the default respawn value - create a dynamic variable called respawn and set it's value to true or false.
14. Update your item by clicking 'APPLY'- very important and easy to miss step.
15. Save your mission and reload it.

A bot called Guard1 should appear at the spot of your marker.
If you come within range of the guard he should shoot at you and try to hunt you down.
If you get away, or when you die, he should return to his post.

I hope the resource helps other people get up and running with some AI code in their game.

And again, I'd like to thank the other members of this website whose code has been used in several places in the scripting to make this all work.

Mark H.

P.S. I've also included my AIPatrol class files with this - to install it follow the same instructions as for AIGuard, just substitute AIPatrol where AIGuard appears in the instructions. They can both be run at the same times with no problems.

P.S.S. 11/28/04 - I modified the AIPatrol.cs file to correct for a couple of typos.

P.S.S.S 12/3/04 - Added ammo and health seeking capabilities and fixed some errors. (Read posts below - or file in .zip for full details.)