Unity3D New Input System: Is it really so hard to stop UI clickthroughs (or figure out if cursor is over a UI object)?

Question

Even the official documentation has borderline insane recommendations to solve what is probably one of the most common UI/3D interaction issues:

If I click while the cursor is over a UI button, both the button (via the graphics raycaster) and the 3D world (via the physics raycaster) will receive the event.

The official manual: https://docs.unity3d.com/Packages/[email protected]/manual/UISupport.html#handling-ambiguities-for-pointer-type-input essentially says "how about you design your game so you don't need 3D and UI at the same time?".

I cannot believe this is not a solved problem. But everything I've tried failed. EventSystem.current.currentSelectedGameObject is sticky, not hover. PointerData is protected and thus not accessible (and one guy offered a workaround via deriving your own class from Standalone Input Module to get around that, but that workaround apparently doesn't work anymore). The old IsPointerOverGameObject throws a warning if you query it in the callback and is always true if you query it in Update().

That's all just mental. Please someone tell me there's a simple, obvious solution to this common, trivial problem that I'm just missing. The graphics raycaster certainly stores somewhere if it's over a UI element, right? Please?

Answer 1

Your frustration is well founded: there are NO examples of making UI work with NewInput which I've found. I can share a more robust version of the Raycaster workaround, from Youtube:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.InputSystem;
using UnityEngine.UI;

/* Danndx 2021 (youtube.com/danndx)
From video: youtu.be/7h1cnGggY2M
thanks - delete me! :) */
 
 
public class SCR_UiInteraction : MonoBehaviour
{
public GameObject ui_canvas;
GraphicRaycaster ui_raycaster;
 
PointerEventData click_data;
List<RaycastResult> click_results;
 
void Start()
{
    ui_raycaster = ui_canvas.GetComponent<GraphicRaycaster>();
    click_data = new PointerEventData(EventSystem.current);
    click_results = new List<RaycastResult>();
}
 
void Update()
{
    // use isPressed if you wish to ray cast every frame:
    //if(Mouse.current.leftButton.isPressed)
    
    // use wasReleasedThisFrame if you wish to ray cast just once per click:
    if(Mouse.current.leftButton.wasReleasedThisFrame)
    {
        GetUiElementsClicked();
    }
}
 
void GetUiElementsClicked()
{
    /** Get all the UI elements clicked, using the current mouse position and raycasting. **/
 
    click_data.position = Mouse.current.position.ReadValue();
    click_results.Clear();
 
    ui_raycaster.Raycast(click_data, click_results);
 
    foreach(RaycastResult result in click_results)
    {
        GameObject ui_element = result.gameObject;
 
        Debug.Log(ui_element.name);
    }
}
}
 

So, just drop into my "Menusscript.cs"?

But as a pattern, this is terrible for separating UI concerns. I'm currently rewiring EVERY separately-concerned PointerEventData click I had already working, and my question is, Why? I can't even find how it's supposed to work: to your point there IS no official guide at all around clicking UI, and it does NOT just drop-on-top.

Anyway, I haven't found anything yet which makes new input work easily on UI, and definitely not found how I'm going to sensibly separate Menuclicks from Activityclicks while keeping game & ui assemblies separate.

Good luck to us all.