Multiple hit detection with Raycasting?

Questions & Answers
1

How can I detect whenever two of my colliders got hit by the raycast at the same time?

Here is my current code:

for(int i = 0; i < Input.touchCount; i++)
	{

		Touch touch = Input.GetTouch(i);

			Ray ray = camera.ScreenPointToRay(Input.touches*.position);*

  •  	Physics.Raycast(ray, out hit);*

  •  	//If A is touched*

  •  	if(hit.collider.tag == "A")*

  •  		{*

  •  			Debug.Log("A");*

  •  		}*

  •  	//If B is touched*

  •  	if(hit.collider.tag == "B")*

  •  		{*

  •  			Debug.Log("B");*

  •  		}*

  •  	//If A and B is touched at the same time*

  •  	if(hit.collider.tag == "A" && hit.collider.tag == "B")*

  •  		{*

  •  			Debug.Log("C");*

  •  		}*

  • }*
    What I want here to happen is to have Debug.Log("C"); executed.
    But instead the things being executed are Debug.Log("A"); and Debug.Log("B");
    I don’t want “A” and “B” executed, I only want “C”.
    EDIT: “C” does not get executed. Only A and B.
    Is there a simple way I can do this?
    Thanks!!

3

I had the same problem and came here, but another answer here rather confused me in my case, unfortunately, so that I leave another approach that effectively worked for me under Unity 2017.3.0f3. I hope it could help some others.

The point is that Raycast method can have a Layer Mask, with which the raycast only sense the objects that belong to the specific layers.

If you have the multiple objects to raycast, belong to different Layers, by raycasting to the same Ray by Layer, you can virtually hit both of them.

In my case, it is more effective than hitting everything over the ray.

Firstly, prepare your GameObjects as each of them belongs to a specific Layer.

Then, the raycast code would be like:

var ray = mainCamera.ScreenPointToRay(Input.mousePosition);
RaycastHit hit0 = new RaycastHit();
RaycastHit hit1 = new RaycastHit();
if (Physics.Raycast(ray, out hit0, Mathf.Infinity, 1 << LayerMask.NameToLayer("Item"))
    && hit0.collider)
    print("Raycast hit one of items");
if (Physics.Raycast(ray, out hit1, Mathf.Infinity, 1 << LayerMask.NameToLayer("World"))
    && hit1.collider)
    print("Raycast hit one of world");

By the way, Layer Mask is a set of Layers, which is a bit map data, although you would see it as int value in debuggers. Each Layer is represented as int data, and by converting it to bits data, you can bundle multiple Layers into a Layer Mask.

For example, if you’d like to get a raycast hit from one of the game objects belonging to either “Item” or “Player” Layer, then code would be:

Physics.Raycast(ray, out hit0, Mathf.Infinity, (1 << LayerMask.NameToLayer("Item")) ^ (1 << LayerMask.NameToLayer("Player"))
2

i did this for you but i leaved somethings for you to fix yourself.Sorry :smiley: but if you cant fix it just let me know i’ll do it for you but please try.If you find this answer helpful please vote.Hehe :smiley:
Things To fix:
1.Raycast hit the Object
2.TouchScreen

using UnityEngine;
using System.Collections;

public class Raycast : MonoBehaviour {
    //public GameObject CubeA;
    //public GameObject CubeB;
    private Ray ray;
    private RaycastHit hit;
    public bool AisTouch;
    public bool BisTouch;

    // Use this for initialization
    void Start () {
        AisTouch = false;
        BisTouch = false;

    }

    // Update is called once per frame
    void Update () {

        ray = Camera.main.ScreenPointToRay(Input.mousePosition);

        if (Physics.Raycast(ray,out hit, Mathf.Infinity) && Input.GetMouseButtonDown (0))
        {

            if(hit.collider.gameObject.tag == "Wood");
            {
                BisTouch = true;
                Debug.Log ("B");
            }
        }
        if  (hit.collider.gameObject.tag == "Grass");
        {
            AisTouch = true;
            Debug.Log ("A");
        }

        if (AisTouch && BisTouch == true);
        {
            Debug.Log ("C is Done");
        }

    } 
}