How to make a simple AI escape script?

Question

I want to make a 2D game. I made scripts for controlling player and simple enemy movement. The enemies should flee from player. I check if player is near to enemy by Vector2.Distance and then make enemy's input equal to player's Input.GetAxis . But it doesn't work correctly and I know why. How to make enemy escape from player?

Answer 1

Answer by TheRefoH · Feb 05, 2014 at 12:05 AM

You could add a collider to the enemy. Use a circle Collider and make it way bigger than your enemy is, than set it "is Trigger". If the player enters the Trigger then let the enemy run in the opposite direction. Its like a big bubble around the enemy and if something enters the bubble the enemy will run away. If the Player leavs the trigger it should stop the enemy from running away instantly.

This might not be the best solution but its a simple one in my opinion.

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kopkinho · Feb 05, 2014 at 12:59 AM 0

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Thank you! I did something like that, with collider, but how to make enemy run in the opposite direction? How to check it?

TheRefoH · Feb 05, 2014 at 11:54 AM 0

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Since it´s a 2D game it should be enough to check the x and y Position of the Player, if the x,y Position is < than the x,y Position of the enemy then you have to increase the x,y of the enemy since this will get him further away. That would be the case if the player is on the left side of the enemy, it has to be the opposite if the player is on the right of the enemy.

I am not on my PC at the $$anonymous$$oment, but i think you can check the x and y position with "transform.position.x"

https://docs.unity3d.com/Documentation/ScriptReference/Transform-position.html

However since i am new to unity i dont know if this is a good solution. Furthermore will this only make your enemy run away on flat ground, if there are obstacles it wont make him jump over them. You maybe could combine it with your own code since the approach that you use for movement is way better.

kopkinho · Feb 05, 2014 at 03:40 PM 0

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Thank you, that works for me, but I used OnTriggerStay2D. But it's not smooth movement.

 function OnTriggerStay2D()
 {
  if (player.position.x < transform.position.x)
      {
         transform.position.x += Time.deltaTime * 10;
 
      }
     else transform.position.x -= Time.deltaTime * 10;
     
  if (player.position.y < transform.position.y)
      {
         transform.position.y += Time.deltaTime * 10;
 
      }
     else transform.position.y -= Time.deltaTime * 10;
 }

TheRefoH · Feb 05, 2014 at 06:26 PM 0

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I am glad I could help a bit. I dont know how to get the movement more smooth, but I am sure there is a way to do it :D

Answer 2

Answer by 7Why · Jun 28, 2014 at 01:01 PM

Here's what i did;

 Vector3 playerPos;
 Vector3 ThisPos;
 GameObject Player;
 
 void Start ()
 {
     Player = GameObject.FindGameObjectWithTag("Player");
 }
 
 void Update ()
 {
     if (Player != null)
     {
         playerPos = Player.transform.position;
     }
 
     thisPos = transform.position;
 
     Collider2D[] collis = Physics2D.OverlapCircleAll(transform.position, minRange); // this creates a range so that when the player enters it the ai will tell it to move away
     foreach (Collider2D colli in collis){ 
         if (colli && colli.tag == "Player")
         { // if object has the right tag...
             transform.position = Vector2.Lerp(thisPos, -playerPos, Time.deltaTime * Speed); // this tells it to move toward the inverse of the players position.
         }
     }
 }

Hope this helps. make sure that you tag your player gameobject as "Player" otherwise it won't do anything.(Speed is the rate at which you want it to move its a Float value so just set to anything to begin with, you can fine tune it later.

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BahamutZeRo · Oct 22, 2015 at 06:25 AM 0

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Hello 7Why, I did trying to use your code but the Inverse direction doesn't work very well thou. It's just keep moving to the left. If you are still around please guide me around. Peaace ^^

How to make a simple AI escape script?

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