Vertical auto-aim with raycasts

Question

So I'm working on a top-down shooter that only allows for x and z control, but need a way to shoot ground enemies as well. This code (much of which I "borrowed" from another question here), is designed to find the closest enemy directly in front of the player and adjust the gun's pitch accordingly. If no enemy is directly ahead, it's just supposed to fire forward (that part works). The problems are that it only detects a hit from very close, no matter what I set the ray distance to, and the end points of the rays stay fixed at their initial z position.

Also, any suggestions to clean up my ugly tag check in the linecast would be cool...

I'm sure this is amateur-hour stuff, but any help is appreciated.

 #pragma strict
 
 public var maxAngle : float = 180;
 public var increments : int = 15;
 public var rayDistance : float = 150;  //Set to 0 for infinity.
 public var sphereCastRadius : float = 2;
 public var targetTag01 : String = "Enemy";
 public var targetTag02 : String;
 public var targetTag03 : String;
 
 
 
 function Start ()
     {
     if (rayDistance == 0)
         {
         rayDistance = Mathf.Infinity;
         }
     
     }
 
 function Update ()
     {
     }
     
 function LateUpdate ()
     {
     }
     
 function FixedUpdate()
     {
     transform.rotation = Quaternion.Euler(0, 0, 0);
     RaycastSweep();
     }
     
 function RaycastSweep()
     {
     var startPos : Vector3 = transform.position; // umm, start position !
     var targetPos : Vector3 = Vector3.zero; // variable for calculated end position
      
     var startAngle : float = ( -maxAngle * 0.5 ); // half the angle to the Left of the forward
     var finishAngle : float = ( maxAngle * 0.5 ); // half the angle to the Right of the forward
      
     // the gap between each ray (increment)
     var inc : float = ( maxAngle / increments );
 
     // step through and find each target point     
     var hit : RaycastHit;
     var targetDistance:float = 215;
     
     for ( var i : float = startAngle; i < finishAngle; i += inc ) // Angle from forward
         {
         targetPos = (Quaternion.Euler( i, 0, 0 ) * transform.forward ).normalized * rayDistance;
          
         // linecast between points
         if ( Physics.Linecast(startPos, targetPos, hit) && ((hit.collider.gameObject.tag == targetTag01) || (hit.collider.gameObject.tag == targetTag02) || (hit.collider.gameObject.tag == targetTag03)))
             {
                 var diff = (transform.position - hit.point);
                 var curDistance = diff.magnitude;
                 if (curDistance < targetDistance)
                     {
                     transform.Rotate(i, 0, 0);
                     targetDistance = curDistance;
                     Debug.Log( "Hit " + hit.collider.gameObject.name );
                     }
              
             // to show ray just for testing
             Debug.DrawLine( startPos, targetPos, Color.green );
             }
         // to show ray just for testing
         Debug.DrawLine( startPos, targetPos, Color.red );
         }
     }

Answer 1

Best Answer

Answer by Fattie · Feb 11, 2013 at 09:52 AM

regarding the tag check it's extremely likely you need to learn about PHYSICS LAYERS.

http://docs.unity3d.com/Documentation/Components/LayerBasedCollision.html

it is absolutely central to game programming in any game engine, hope it helps

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gitoffame · Feb 11, 2013 at 06:00 PM 0

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Thanks for the tip - I removed the tag-check and used layers ins$$anonymous$$d. That should simplify a few things some.

However, my two main problems persist, unfortunately.

gitoffame · Feb 11, 2013 at 08:04 PM 0

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I changed things a bit; now the hit detection seems to work better at further distances, but the endpoints of the rays still don't seem to be updating accordingly when I change my Z position. I can still basically move forward past the end of the raycast sweep.

Updated code:

 #pragma strict
 
 public var maxAngle : float = 180;
 public var increments : int = 15;
 public var rayDistance : float = 150;  //Set to 0 for infinity.
 public var layer$$anonymous$$ask : int = 12;
 
 
 
 function Start ()
     {
     layer$$anonymous$$ask = 1 << layer$$anonymous$$ask;
     if (rayDistance == 0)
         {
         rayDistance = $$anonymous$$athf.Infinity;
         }
     }
 
 function Update ()
     {
     }
     
 function LateUpdate ()
     {
     }
     
 function FixedUpdate()
     {
     RaycastSweep();
     }
     
 function RaycastSweep()
     {
     transform.rotation = Quaternion.Euler(0, 0, 0);
     var startPos : Vector3 = transform.position; // umm, start position !
     var targetPos : Vector3 = Vector3.zero; // variable for calculated end position
      
     var startAngle : float = ( -maxAngle * 0.5 ); // half the angle to the Left of the forward
     var finishAngle : float = ( maxAngle * 0.5 ); // half the angle to the Right of the forward
      
     // the gap between each ray (increment)
     var inc : float = ( maxAngle / increments );
 
     // step through and find each target point     
     var hit : RaycastHit;
     var targetDistance:float = 215;
     var targetRotation:Quaternion;
     
     for (var i : float = startAngle; i < finishAngle; i += inc ) // Angle from forward
         {
         targetPos = (Quaternion.Euler(i, 0, 0 ) * transform.forward).normalized * rayDistance;
          
         // linecast between points
         if ( Physics.Linecast(startPos, targetPos, hit, layer$$anonymous$$ask))
             {
                 var diff = (transform.position - hit.point);
                 var curDistance = diff.magnitude;
                 if (curDistance < targetDistance)
                     {
                     targetRotation = Quaternion.Euler(i, 0, 0);
                     targetDistance = curDistance;
                     Debug.Log( "Hit " + hit.collider.gameObject.name );
                     }
              
             // to show ray just for testing
             Debug.DrawLine( startPos, targetPos, Color.green );
             }
         // to show ray just for testing
         Debug.DrawLine( startPos, targetPos, Color.red );
         }
     transform.rotation = targetRotation;
     }

gitoffame · Feb 12, 2013 at 02:04 AM 0

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To further clarify: The "fan" of raycasts, end points and all, should be moving forward with the ship, but the end points are not.

alt text

c.png (127.8 kB)

gitoffame · Feb 12, 2013 at 11:21 PM 0

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I suspect my problem is in line 51, possibly giving me a world coordinate ins$$anonymous$$d of a relative coordinate... Anyone?

robertbu · Feb 13, 2013 at 12:30 AM 0

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If I understand correctly what you want to do, then your error is in line 36. You are calculating an absolute position for the targetPos. You want tartegPos to follow the ship, so you want something like:

 targetPos = transform.position + (Quaternion.Euler(i, 0, 0 ) * transform.forward).normalized * rayDistance;

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Vertical auto-aim with raycasts

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