Question by mileswells93 · Oct 17, 2020 at 05:33 PM · physics2d collider2d overlap

OverlapBox not working as expected

Hi everyone. I'm trying to create game objects by a player clicking, but only if the created object wouldn't overlap with any others. Relevant block:

 // left click
 if (Input.GetMouseButtonDown(0))
 {
   // mouse position on viewport
   var pos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
   pos.z = 1;
 
   // menu item is selected
   if (activeItem != null)
   {
     var rectSize = this.activeItem.sprite.rect.size;
     var colliderSize = Camera.main.ScreenToViewportPoint(rectSize);
 
     var collidedWith = Physics2D.OverlapBox(pos, colliderSize, 0);
     // if the new object won't overlap, go ahead and create it.
     if (collidedWith == null)
     {
       var newObj = new GameObject(activeItem.label); // create game object
       newObj.AddComponent(System.Type.GetType(activeItem.className)); // add script
       var collider = newObj.AddComponent<BoxCollider2D>(); // add collider
       var renderer = newObj.AddComponent<SpriteRenderer>(); // add sprite renderer
 
       // rendering and positioning stuff 
       renderer.sprite = activeItem.sprite;
       renderer.sortingLayerName = "GameObjects";
       renderer.transform.position = pos;
     }
   }
 }

This mostly works, but still allows overlap on roughly half of an object:

alt text