What is the proper use of WorldToScreenPoint?

I can't seem to find the answer I need anywhere on the forum or answers.. or I'm just too dumb to understand. I keep getting errors when trying to use this function (WorldToScreenPoint). I tried attaching the scripting example provided by Unity to a Cube. Code:

Code (csharp):

1.    
2. using UnityEngine;
3. using System.Collections;
4.  
5. public class example : MonoBehaviour {
6.     public Transform target;
7.     void Update() {
8.         Vector3 screenPos = camera.WorldToScreenPoint(target.position);
9.         print("target is " + screenPos.x + " pixels from the left");
10.     }
11. }
12.     }

In this form I get:

I tried changing the c letter to capital C, then I get this error:

Tried putting:

Code (csharp):

1. Vector3 screenPos = Camera.main.WorldToScreenPoint(target.position);

When I run the game it says:

So how do I use this function ??

 

Camera.main was ok .. im sure you probably have not set the target variable to have a value

 

Not sure why Camera.main does not work. There are many ways to achieve what you need. Here is one:

1. Create a property camera in your example class.

Code (csharp):

1.     public Camera camera = null;
2.  

2, In Inspector drag your main camera to that property.. Now you can use it from Update() method

 

This isn't ideal because 'camera' is already a member of Component (and GameObject) which refers to the camera attached to 'this' object. So if you simply attach a Camera to the GameObject in question then there is no need for the additional declaration or if you would rather assign via Inspector then a different variable name is in order.

 

Can I make it work with transform.position instead of target?
Can someone please post a code? (PS I've tried even declaring public Camera camera but it doesn't work)

 

Agreed with a different variable name point. I was just trying to keep the name to be the same as in the original example. As far as attaching it as a component - I don't think it's what asdx wants to achieve here.

 

asdx - after you declared a public Camera property, did you drag your camera into that property in the Inspector?

 

Here's a quick working example that will throw an error up if things aren't set up correctly.

Code (csharp):

1.  
2. using UnityEngine;
3.  
4. public class Example : MonoBehaviour
5. {
6.     public Transform target;  // set via Inspector
7.     void Awake()
8.     {
9.         if (target == null) Debug.LogError("Set target variable in Inspector!");
10.         if (Camera.main == null) Debug.LogError("There is no camera tagged as 'Main Camera'!");
11.     }
12.  
13.     void Update()
14.     {
15.         Vector3 screenPos = Camera.main.WorldToScreenPoint(target.position);
16.         Debug.Log("Screen position is: " + screenPos);
17.     }
18. }
19.  

 

It seems that my stupid mistake was that I did not tagged my Main Camera. I previously deleted it, and was naming, not tagging it. I realized it just before reading the posts so I believe KelsoMRK's script would of spot it easily. Ty so much guys! I was in a real pickle