WorldSpace vs LocalSpace problem

Question

Hi, I have a section of code which detects whether an object is within another objects viewcone. This works as anticipated (grabbed from other areas of the forum), however, it always forward in world space, and I'd like to alter it so it's alway looks forward in local space (so if the character the script is attached to turns, the viewcone turns with the way he is moving). I've been struggling with it and can't seem to get the results I'm after. Could anyone advise me what to change in order to get this working? I pass the transform of an object to CheckCanSee, this then checks the angle (and also draws the viewcone, which again is locked to world space). Thanks for any pointers

     public bool CheckCanSee (Transform canISeeThis)
     {
         if (drawViewcone) {
             // Draws the viewcone
             DrawLine (distanceThreshold, fieldOfView/2.0f, 0.0f); 
             DrawLine (distanceThreshold, (-fieldOfView)/2.0f, 0.0f); 
         }
     
         Vector3 direction = canISeeThis.position - transform.position;
  
         // Calculate angle to object
         angleToObject = Vector3.Angle (direction, transform.forward);
         Debug.Log ("Object is " + angleToObject + " degrees.");
   
         if (angleToObject > ( fieldOfView * 0.5f ) ) {
             // The target is outside the field of view!
             Debug.DrawLine (transform.position, canISeeThis.position, new Color (1.0f, 0.0f, 0.0f, 1.0f), 0.5f);
             Debug.Log ("Outside FOV");
             return false;
         }
  
         Debug.DrawLine (transform.position, canISeeThis.position, new Color (0.0f, 1.0f, 0.0f, 1.0f), 0.5f);
  
         return true;
     }
     
     /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
     /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
     /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
     // Draws a line, given specific angles    
     private void DrawLine (float distance, float xAngle, float yAngle)
     {      
  
         float x =  transform.position.x + distance * Mathf.Sin (xAngle * Mathf.Deg2Rad) * Mathf.Cos (yAngle * Mathf.Deg2Rad);
         float y = transform.position.y + distance * Mathf.Sin (xAngle * Mathf.Deg2Rad) * Mathf.Sin (yAngle * Mathf.Deg2Rad);
         float z = transform.position.z + distance * Mathf.Cos (xAngle * Mathf.Deg2Rad);
 
         Vector3 finalPos = new Vector3 (x, y, z);            
 
         Debug.DrawLine (transform.position, finalPos, new Color (0.0f, 0.0f, 1.0f, 0.3f), 0.8f);
     }

Answer 1

Answer by ScroodgeM · Sep 05, 2012 at 07:09 PM

as i understood your question, you just need a check if object is in view cone?

using UnityEngine; using System.Collections; public class ViewConeIn : MonoBehaviour { public Transform ObjectToViewCheck; public float maxDistance = 10f; public float maxAngle = 60f; void OnGUI() { float distance = Vector3.Distance(transform.position, ObjectToViewCheck.position); float angle = Vector3.Angle(transform.forward, ObjectToViewCheck.position - transform.position); GUI.color = distance > maxDistance ? Color.red : Color.green; GUI.Box(new Rect(5, 5, 100, 30), string.Format("distance: {0}", distance.ToString("0.0"))); GUI.color = angle > maxAngle ? Color.red : Color.green; GUI.Box(new Rect(5, 40, 100, 30), string.Format("angle: {0}", angle.ToString("0.0"))); } }

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AntLewis · Sep 05, 2012 at 07:25 PM 0

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No sorry I think you've misunderstood. The viewcone always points forward in world space, but I want it to be forward in local space (so it faces teh direction that the characer is moving). Thanks!

ScroodgeM · Sep 05, 2012 at 07:27 PM 0

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i'd use transform.forward here in my script, it is local's forward direction translated to world space.

attach script to some object, create another object and reference second object to this script as object to look at. then run the game and move/rotate objects.

AntLewis · Sep 05, 2012 at 08:12 PM 0

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Ah I see - can I ask, if the target object is directly in front of the object that the script is attached to, it reduces to around 4 or 5 degrees then increases again - should it be hitting '0' degrees? Thanks again for the help/

ScroodgeM · Sep 06, 2012 at 04:34 AM 0

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if object directly in front of the object you will get 0 degrees, but the object in your case me thinks a little up or down from looking object and moving it in horizontal axis will not make 0 degrees. be sure that both vertical and horizontal relative position is close to zero to get 0 degrees

WorldSpace vs LocalSpace problem

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