How to utilize Screen.Width/height? --Unity3d

Question

I am trying to randomly instantiate things within the screen in Unity 2d

I tried to use Screen.Width and Screen.Height but the objects were appearing way off the screen. I realized that this was because Screen.width/height returns the length in pixels and unity goes by its own unit.

For example, this didn't work. The bomb appears way off Screen

var randomX = Random.Range(-Screen.width/2, Screen.width/2);
var randomY = Random.Range(-Screen.height/2, Screen.height.2);
var spawnPoint:Vector2 = new Vector3(randomX , randomY);
Instantiate( bomb, spawnPoint, Quaternion.identity );

Is there a way to convert the Pixels to Unity units?

Answer 1

There sure is, use ScreenToWorldPoint .

Note that the API informs you the bottom left of the screen is 0,0, so you will want to change your randomX/Y accordingly.

Answer 2

Make this:

Vector3 worldToScreen = Camera.main.WorldToScreenPoint(transform.position);

var randomX = Random.Range(-worldToScreen.x , worldToScreen.x);
var randomY = Random.Range(-worldToScreen.y , worldToScreen.y);
var spawnPoint:Vector2 = new Vector3(randomX , randomY);
Instantiate( bomb, spawnPoint, Quaternion.identity );