Achieving something like LookAt but with the X axis.

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I'm working on a 2D scene and have been trying to come up with a way to get the results of look at but on the X axis, that is my current objects right faces the target. I found a way around it by using parent objects but it's a jumbled mess. It gives me problems when I use colliders2D and mainly with sprites as these can't be seen if you rotate the objects. So I am wondering if some of you have had this problem before and if maybe you can lend me a hand.

Answer 1

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Answer by ashique · Feb 06, 2014 at 06:06 AM

Calculate the direction between current Object and Target object e.g

Vector3 dir = (CurrentObject's Position - TargetObject position). normalized;

CurrentObject.transform.right = dir;

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robertbu · Feb 06, 2014 at 06:24 AM 1

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In my experience, the direct assignment to transform.right sometimes results in the sprite flipping.

superluigi · Feb 08, 2014 at 12:32 AM 0

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There's only one problem with your code. When you use LookAt if the target goes behind the object, the object will turn around (do a 180) and continue looking at them. With your code the object just keeps on turning and is upside down if the target goes behind them. I'm working to find a solution to this last part.

Answer 2

Answer by robertbu · Feb 06, 2014 at 05:56 AM

Since this is 2D and the right side of your object is consider the 'forward' side to be pointed at the target, you can do it this way:

 Vector3 dir = target.position - transform.position;
 float angle = Mathf.Atan2(dir.y,dir.x) * Mathf.Rad2Deg;
 transform.rotation = Quaternion.AngleAxis(angle, Vector3.forward);

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superluigi · Feb 06, 2014 at 11:30 PM 0

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There's only one problem with your code. When you use LookAt if the target goes behind the object, the object will turn around (do a 180) and continue looking at them. With your code the object just keeps on turning and is upside down if the target goes behind them. I'm working to find a solution to this last part.

robertbu · Feb 08, 2014 at 12:46 AM 0

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This rotation issue is inherit with a 2D. A fix is to detect when you are on the left side and change the texture. You can check left/right by checking the angle:

 if (angle > 90 || angle < -90) {
     Debug.Log("The target is on the left side of me");
 }

Another solution would be to convert the point to local coordinates and test:

 Vector3 local = transform.InverseTransformPoint(target.position);
 if (local.x < 0.0) {
     Debug.Log("The target is on the left side of me");
 }

superluigi · Feb 08, 2014 at 04:30 AM 0

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I'm gonna try it out. I know in the reference it says that LookAt points the objects up toward the worlds up vector so if your object starts turning upside down it'll do a 180 and fix it. I've been trying to replicate that.

Answer 3

Answer by RyanZimmerman87 · Feb 06, 2014 at 06:00 AM

Might need more info but I think what you need is something like:

 //playerLookVector can be where you want to look
 
 //playerTransform is whatever object you want to look at the playerLookVector
 
 //lookObject is the object you want to lookAT
 
 
 //this.PlayerTransform.position.y will cause the player too look straight forward
 
 playerLookVector = new Vector3 (lookObject.transform.position.x, 
                                             this.playerTransform.position.y, lookObject.transform.position.z);
 
 this.playerTransform.LookAt(playerLookVector);

That's a 3d example but pretty sure you can still use it or do something similar with Vector2 instead of Vector3.

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Achieving something like LookAt but with the X axis.

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