How to avoid placing object behind buttons?

Question

Google Tango and Unity related question.

Using this tutorial we can place an object on the surface by tapping the screen.

Here is the code:

using UnityEngine;
using System.Collections;

public class KittyUIController : MonoBehaviour
{
    public GameObject m_kitten;
    private TangoPointCloud m_pointCloud;

    void Start()
    {
        m_pointCloud = FindObjectOfType<TangoPointCloud>();
    }

    void Update ()
    {
        if (Input.touchCount == 1)
        {
            // Trigger place kitten function when single touch ended.
            Touch t = Input.GetTouch(0);
            if (t.phase == TouchPhase.Ended)
            {
                PlaceKitten(t.position);
            }
        }
    }

    void PlaceKitten(Vector2 touchPosition)
    {
        // Find the plane.
        Camera cam = Camera.main;
        Vector3 planeCenter;
        Plane plane;
        if (!m_pointCloud.FindPlane(cam, touchPosition, out planeCenter, out plane))
        {
            Debug.Log("cannot find plane.");
            return;
        }

        // Place kitten on the surface, and make it always face the camera.
        if (Vector3.Angle(plane.normal, Vector3.up) < 30.0f)
        {
            Vector3 up = plane.normal;
            Vector3 right = Vector3.Cross(plane.normal, cam.transform.forward).normalized;
            Vector3 forward = Vector3.Cross(right, plane.normal).normalized;
            Instantiate(m_kitten, planeCenter, Quaternion.LookRotation(forward, up));
        }
        else
        {
            Debug.Log("surface is too steep for kitten to stand on.");
        }
    }
}

I have buttons on the screen, and when I press them I also place an object on the surface behind it.

How can I avoid it? So if I'm pressing a button I don't want to place an object at the same time.

If I have a function which executes when I tap on the screen, how can I prevent it from executing if I click on a button on the screen?

please post your code so we can figure out where the issue is. — ryeMoss, Jul 11 '17 at 15:36

score 1 · Answer 1 · answered Jul 11 '17 at 17:24

One way to accomplish this would be to add a tag to your buttons, cast a ray on touch, and see if the ray is colliding with an object with the button's tag.

    if (Input.touchCount == 1)
    {
        // Trigger place kitten function when single touch ended.
        Touch t = Input.GetTouch(0);
        Ray ray = Camera.main.ScreenPointToRay(t.position);
        RaycastHit hit;

        if(t.phase == TouchPhase.Ended && Physics.Raycast(ray,out hit,100))
        {
            if(hit.collider.tag == "button")
            {
                //do button stuff
            }
            else
            {
                PlaceKitten(t.position);
            }
        }
    }

Thank you, I added "button" tag to the button, but for some reason when I'm using this code I can't place an object at all, no matter if I click on the button or anywhere else on the screen. For testing I moved "PlaceKitten" function there where You have "do button stuff", but if I click the button nothing happens. — Rumata, Jul 29 '17 at 14:28

score 1 · Answer 2 · answered Jul 11 '17 at 19:22

I've answered this before but couldn't find the duplicate to close this question. When I do find it, I will close it.

You need to check if the mouse position is over the UI before considering that as a valid click.

This is done with the IsPointerOverGameObject function.

void Update()
{
    if (Input.touchCount == 1)
    {
        // Trigger place kitten function when single touch ended.
        Touch t = Input.GetTouch(0);
        if (t.phase == TouchPhase.Ended)
        {
            //Make sure we are not over the UI
            if (!UnityEngine.EventSystems.EventSystem.current.IsPointerOverGameObject())
            {
                Debug.Log("Clicked outside the UI");
                PlaceKitten(t.position);
            }
        }
    }
}

For a touch screen devices, you have to pass the fingerId to the function:

void Update()
{
    if (Input.touchCount == 1)
    {
        // Trigger place kitten function when single touch ended.
        Touch t = Input.GetTouch(0);
        if (t.phase == TouchPhase.Ended)
        {
            //Make sure we are not over the UI
            if (!EventSystem.current.IsPointerOverGameObject(Input.GetTouch(0).fingerId))
            {
                Debug.Log("Touched outside the UI");
                PlaceKitten(t.position);
            }
        }
    }
}

Thank you, but for some reason, it doesn't prevent me from placing objects when I'm clicking on the buttons. Should I change anything in the scene, maybe add any tags to the objects? At the moment my UI is in render mode "Screen space - overlay". — Rumata, Jul 29 '17 at 14:30

How to avoid placing object behind buttons?

2 Answers2