2D Function analyzing if there is a Gameobject where you click ?

Question

Hi everybody !

I'm making a little game with objects appearing when I click. I have this code actually making things work : everytime I use the mouseclick a Gameobject is created where I click on the 2d game I created.

  //Changed to an array of objects assign as many as you have in inspector
     var boxes : GameObject[];
     var boxCounter : int;
      
     function Update()
     {
     if(Input.GetMouseButtonDown(0))//Checks to see if left mouse button was clicked.
     {
     CreateBox();
     }
     }
      
     function CreateBox()
     {
     var mousePos : Vector2 = Input.mousePosition;
      
     //Depth you want the center of the object to be is z which I used zero
     var boxPos : Vector3 = camera.ScreenToWorldPoint(mousePos.x, mousePos.y, 0);
      
     //I used the perfab box's rotation here but you can enter what you'd like as a euler using Quaternion.Euler(x,y,z)
     Instantiate(boxes[boxCounter], boxPos, boxes[boxCounter].transform.rotation);
      
     //This will increment if there are more boxes or reset to 0 if it is the last one.
     if(boxCounter == boxes.length-1)
     {
     boxCounter = 0;
     }else{
     boxCounter ++;
     }
     }

I want to add a function to avoid the creation of the object if there is already another one where I clicked. I don't know if I can do a simple function like If onclick there is a gameobject nothing happened; or if I have to do something like when I click create a gameobject, if collision cancel it, if not go for the Createbox function. I don't know exactly how to do that, any idea?

Thanks in advance !

Answer 1

I suggest using Physics.OverlapSphere with the OnClick method.

This way you can set the radius to decide on how far from other boxes you can place the new box.

EDIT:

I noticed you are using unity 2d, so a better function would be Physics2D.OverlapCircle.

Bellow is a tested example of how I made this work.

 var boxes: GameObject[];
 var boxCounter: int;
 
 function Start() {
     boxCounter = 0;
 }
 
 // Update is called once per frame
 function Update() {
     if (Input.GetMouseButtonDown(0)) //Checks to see if left mouse button was clicked.
     {
         CreateBox();
     }
 }
 
 function CreateBox() {
     var mousePos: Vector2 = Input.mousePosition;
 
     //I used 10 for the depth here because camera is at -10. This means all boxes will be created at Z = 0
     var boxPos: Vector3 = Camera.main.ScreenToWorldPoint(Vector3(mousePos.x, mousePos.y, 10));
 
     //OverlapCircle helps us know if there is a collider in a specific circle
     //So we overlap a circle where we want to place the new box
     var collider = Physics2D.OverlapCircle(Vector2(boxPos.x, boxPos.y), 0.5f);
 
     //If no other colliders (boxes) exist at the new position, create our new box
     if (collider == null) {
         Instantiate(boxes[boxCounter], boxPos, boxes[boxCounter].transform.rotation);
     }
 
     //This will increment if there are more boxes or reset to 0 if it is the last one.
     if (boxCounter == boxes.length - 1) {
         boxCounter = 0;
     } else {
         boxCounter++;
     }
 }

Answer 2

Answer by KiraSensei · Apr 30, 2014 at 08:38 AM

I would suggest you to handle the problem like this :

OnClick -> make a raycast (see doc)
if the raycast hits a collider (this supposes that your created game objects have one), do nothing
else you create your game object.

Instantiate and destroy are far more heavier than a ray cast.

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Answer 3

Answer by Lolifius · May 01, 2014 at 02:38 PM

Hi ! Thanks about this. How do you make the function overslap work in tis case? I tried without succes ...

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korbul · May 02, 2014 at 11:47 AM 0

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I updated my answer above.

Answer 4

Answer by Noob_Vulcan · May 02, 2014 at 12:20 PM

 if (Input.GetMouseButtonDown(0)) {      //when user touches the screen
                 RaycastHit hit = new RaycastHit ();
                 if (Physics.Raycast (ray, out hit)) {
                     //if it is a box
                     if (hit.transform.CompareTag ("Box")) {
                     //then do nothing    }
                     else
                       CreateBox()
             }

}

Just put this code in your update function ..and you are good to go

Note* Set you box tag as "Box"

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Noob_Vulcan · May 02, 2014 at 12:20 PM 0

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there is 2d raycast also ..But i never used that so cant tell u abt that

2D Function analyzing if there is a Gameobject where you click ?

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