How do I cause New GUI elements to intercept raycasts?

Unity Engine
1

Disclaimer: This thread may not be in the right place; I’m not sure where it should go. If it’s felt that this needs to be moved to a more appropriate place, please do so.

In my current project I’m prototyping, I’ve hit a snag. You can see for yourself here.

When the match loads up, you are on the Knights side. When you click the castle, you get a command bar for it. When you click the only action button available at present, you’ll notice the WebGL player will freeze entirely, due to a Null Reference exception.

I know exactly why this NullRef is occurring - I have selection code that raycasts to a point that the camera can see; if the cast hits terrain the current selected unit is deselected (set to null). What’s ultimately going on is that you’re issuing a command from a null unit, thus the nullref. However, it’s also a UX bug, because the user may want to spawn multiple units in one go - I can’t just creatively code my way around this and call it ‘done’.

What I used to would do in the old GUI system is put a ‘blocker’ collider behind the GUI which would absorb the raycast, but that’s not an option here becuase the New GUI stuff is all 2D sprite-y stuff. This leads straight into my question…

Question - How do I get the new GUI system to intercept raycasts, such that it doesn’t keep going to the terrain?

2

Hm, you could add colliders to you UI elements?

3

What kind of colliders would I use?

4

2D box or circle colliders depending on the type of UI element? I don’t know, I am basically guessing around. Never tried this, sorry. :slight_smile:

5

I tried to add a 2D Box Collider to the background GUI element, but that had no effect, possibly because I’m not sure how to even position the collider. I could have sworn the New GUI should be able to be set up to absorb raycasts - Unity isn’t this incompetent, that’s my job. :wink:

Just to be entirely sure of my assumptions, this is my UnitSelectionManager, which is the thing that does the raycast from the camera. Am I using the right stuff? I know the New GUI stuff had an entire new namespace that when I was getting started with it I had to use; it may well be that using the ‘old’ raycasting setup isn’t correct, and I need to do something else. I don’t know. This is really frustrating.

6

What about using the new Raycasters?

Before running your raycast, you can use your GraphicRaycaster to determine if the point hits a UI element. If it does, then skip the raycast.

7

I think you’re looking for EventSystemManager.currentSystem.IsPointerOverEventSystemObject()

8

I’m not at a place where I can run WebGL. I read the OP as arbitrary raycasts. But if it’s just the mouse, IsPointerOverGameObject() is what you want, as StarManta writes.

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@TonyLi - I added a check that calls this method…

public bool IsMouseOverUIObject()
{
    bool result = EventSystem.current.currentSelectedGameObject != null;
    DebugMessage("Is the mouse over a UI object?  Answer: " + result);

    return result;
}

…which let the code do what I need it to. One caveat that I intend to go back and look at when I’m polishing this thing - I would really like it if the panels also absorbed raycasts as well. That being said, this is enough to make the GUI serviceable enough to show to people, when I get the other bits of this taken care of.

10

Here is one I prepared earlier

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