Locate a game object using rays

Question

Ok,

I need to check if a gameObject is in the cameras view or not. I have got that working, (On a basic level), with Renderer.IsVisible. Ok. But now I need a away to check if he is be$$anonymous$$nd a tree, or be$$anonymous$$nd an object. I believe the easiest way to do t$$anonymous$$s, would be to use a ray.

I tried using line cast, but it didn't work. It shot off in a different direction.

         Debug.DrawRay(you.position, slenderMan.position, Color.green);
     if (!Physics.Linecast (you.position, slenderMan.position))
     {
     Debug.Log("He is be$$anonymous$$nd a collider");
     }

The debug line was never called, because when I looked in the screen view, the ray (Shown in green) was pointing in a different direction.

Is there a way to fix t$$anonymous$$s? As in, line cast to a specific object to detect colliders?

Thanks.

Answer 1

Best Answer

Answer by Kacer · Aug 22, 2012 at 09:42 AM

Is there a reason why you're not using a raycast instead?

From my interpretation of the documentation you're checking whether there is a collider between you and the target, it returns true if there is a collider. So you should be getting a message saying that he is be$$anonymous$$nd a collider when he isnt,

As for the odd error you're getting, make sure the target or the origin of the ray isnt a c$$anonymous$$ld of somet$$anonymous$$ng, as that might get you some odd results.

I've tried doing somet$$anonymous$$ng similar myself, here's the code i made:

 public GameObject target;
 
     void Update () {
         Debug.DrawLine(transform.position,target.transform.position,Color.cyan);
         if(!Physics.Linecast(transform.position,target.transform.position)){
             Debug.Log("Hai World");
         }
     }

as it is written here the console prints "hai world" when there isnt a collider between the origin and the target.

Hope t$$anonymous$$s helped :)

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suctioncup · Aug 22, 2012 at 10:16 AM 0

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Thankyou for this,

I figured out (partly) what my problem was. I needed to remove the !, but I also had to remove the collider on the second game object, otherwise the line cast was detecting that collider.

Kacer · Aug 22, 2012 at 10:53 AM 1

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You're welcome, remember to mark the question answered if you found out what the problem was, it helps other people who might have the same issues :)

suctioncup · Aug 22, 2012 at 10:55 AM 0

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Its not fixed yet. The linecast detects the collider on the second object, which causes imprecise data. I need both gameObjects to have a collider, but detect when a third collider is added it the middle. http://forum.unity3d.com/threads/148342-Unity-Linecast-not-detecting-colliders

Kacer · Aug 22, 2012 at 10:58 AM 1

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You could use a layermask; http://docs.unity3d.com/Documentation/ScriptReference/Physics.Linecast.html

using layermasks lets you decide what colliders should be detected by the layermask, ie; place the characters on layer 1 and the object on layer 2, then have the linecast ignore objects on layer 1.

Simple \o/

suctioncup · Aug 23, 2012 at 11:32 AM 0

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Thankyou! This really helped, and now I now how to use layermasks, (Albeit of a basic level)

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