How do I detect when mouse passes over an object?

Questions & Answers
1

I’ve been loocking for this for a while, but all I’ve found was OnMouseOver() function. I don’t konow why but this doesnt work anymore.
Raycast doesnt wok either.
I need that when the mouse is over an object, image is showed instead of the normal cursor
Please help!

3

Be sure the objects you wish to detect have a Collider attached, and use a RayCast, or OnMouseOver.

You didn’t specify your language so I’ll give a JS and CS example.

JS Example of Raycast:

//Attach this script to your Main Camera, or an Empty GameObject.

#pragma strict

var ray : Ray;
var hit : RaycastHit;

function Update () 
{
	ray = Camera.main.ScreenPointToRay(Input.mousePosition);
	if(Physics.Raycast(ray, hit))
	{
		Debug.Log(hit.collider.name);
	}
}

C# Example on Raycast:

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour
{
	Ray ray;
	RaycastHit hit;
	
	void Update()
	{
		ray = Camera.main.ScreenPointToRay(Input.mousePosition);
		if(Physics.Raycast(ray, out hit))
		{
			print (hit.collider.name);
		}
	}
}

JS Example on OnMouseOver():

//Attach this to each object that will need to be detected. This is why I prefer Raycast, becasue with Raycast, you only need one instance of the script.

#pragma strict

function OnMouseOver() 
{
	print(gameObject.name);
}

C# Example on OnMouseOver():

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour
{
	void OnMouseOver()
	{
		print (gameObject.name);
	}
}
2

These links have everything that you need:

4

There are 3 options to solve this problem. All of them will trigger the MonoBehavior method OnMouseOver. In my case the issue was trying to detect the mouse via trigger area.

  1. Use a collider (set to trigger false)
  2. Use a collider (set to trigger true). You will need to set your physics settings to force triggers to be detected by raycasts. This is generally not a good idea as every trigger in your game will now intercept raycasts
  3. Create a new layer called Interactions and set it to interact with nothing on the collision matrix. Create a collider and object as normal with the new layer. The important part here is that you have a script that emits an event on the object so other scripts can make use of the mouse events

In my case option 3 did the trick. I can now have invisible trigger detection areas without affecting any other system. It works for keyboard / mouse and could easily be extended to work with a gamepad. Option 1 and 2 both created a giant mess for me.