Moving objects to point of touch on iPhone.

Question

Hello. I'm hoping someone will point me in the right direction, even if this might be a dumb question... I'm working on an iPhone AR app and I'm able to get an object to show up where I tap my finger. But I would like it to move rather than just show up! So I guess I should use Translate, not position, but I can't get that to work with the ScreenToWorldPoint thing. Tried numerous different combinations of code.

Is this maybe much more complex than I think?

I'd be very grateful if somebody could help me out!

Iv'e read this post (among many others) but it doesn't get me all the way there... http://answers.unity3d.com/questions/225988/moving-an-object-to-the-position-of-touch.html

function Update () {

 for(var touch : Touch in Input.touches) {
 if(touch.phase == TouchPhase.Ended) {
     Debug.Log("Touched...");
     
     
     var curX = Input.GetTouch(0).position.x;
     var curY = Input.GetTouch(0).position.y;
     
     //transform.Translate = Camera.main.ScreenToWorldPoint(new Vector3 (curX, curY, 1000));
     transform.position = Camera.main.ScreenToWorldPoint(new Vector3 (curX, curY, 1000));

 } 
 }
 }

EDIT: I've now been trying to combine Vector3.MoveTowards or Vector3.Lerp with Camera.main.ScreenToWorldPoint. Can this be done?

Answer 1

Answer by gregzo · Apr 11, 2012 at 02:26 PM

You're only checking when the user releases a finger (TouchPhase.Ended). To Translate effectively, start a coroutine (don't try to run this code!):

 if(touch.phase == TouchPhase.Ended) {
   
 MoveObjectHereInXSeconds(Input.GetTouch(i).position, 1.2); //1.2 s for example
 }
 }
 function MoveObjectHereInXSeconds(fingerPos:Vector2, time : float)
 {
     //write your own function here, starting with while(theObjectIsNoteWhereIWantIt)
     //MoveIt
     //Don't forget to yield;
 }

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Answer 2

Answer by JayMHelpsU · Apr 11, 2012 at 03:01 PM

Ok well is it more of a glide motion you are looking for? If so try this out.

var speeds : Int

for(var touch : Touch in Input.touches) { if(touch.phase == TouchPhase.Ended) { Debug.Log("Touched..."); var curX = Input.GetTouch(0).position.x; var curY = Input.GetTouch(0).position.y; Pos = Instantiate(curX, curY, 1000); Pos.rigidbody.AddForce(transform.forward * speeds); } }

Try this

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maryhary · Apr 12, 2012 at 06:57 AM 0

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Hi! I tried this, but I get the error message BCE0044: unexpected char: 0xAD. at this line: Pos.rigidbody.AddForce(transform.forward * speed);

Can't make out what the problem is...

maryhary · Apr 12, 2012 at 07:24 AM 0

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Ok, so I changed to FixedUpdate, which got rid of that message. But now it has a problem with "Pos". Says it's an $$anonymous$$ identifier...

Answer 3

Answer by Adamcbrz · Apr 11, 2012 at 02:29 PM

I am assuming you want it to move to the point you tap not just jump to the position. If thats the case you will have to set a variable to be your destination and then Translate over a set time. This is not tested code but can get you in the right direction. Another option is to use an code animation tool like iTween.

 var destination : Vector3;
 var speed : float = 10;
 function Update() {
     if(touch.phase == TouchPhaseEnded)
     {
         var curX = Input.GetTouch(0).position.x;
         var curY = Input.GetTouch(0).position.y;
         destination = Camera.main.ScreenToWorldPoint(new Vector3 (curX, curY, 1000));
     }

     if(destination != transform.position)
     {
         transform.position = (transform.position - destination).normilize * speed;
     }
 }

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maryhary · Apr 12, 2012 at 08:33 AM 0

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Hello! I tried this (but normalized ins$$anonymous$$d of normilize) and it runs fine, but the object doesn't move at all. Doesn't even jump...

Answer 4

Answer by maryhary · Apr 11, 2012 at 03:00 PM

I will look into this, but I just want to check what you mean by "You're only checking when the user releases a finger (TouchPhase.Ended)". What I want is to tap the screen, and then for an object to move to the location of the tap, is this not correct then? Just making sure you don't think I mean dragging things :)

Thank you for your time!

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gregzo · Apr 11, 2012 at 03:34 PM 0

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@maryhary Please use comments and don't post a new answer in such cases...

And indeed, I don't mean dragging. In your script, if(touch.phase == TouchPhase.Ended) implies that all follwoing instructions (included in the curly braces, of course) will only be executed once, during the frame the finger was lifted in. Of course, to "glide" an object, you need to update it's position more than once!

Moving objects to point of touch on iPhone.

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