Click handling

[EtienneBruines]

How should clicks be handled according to the ECS?

In javascript/html, there's some kind of propagation: the foremost element is clicked, then passed along to any other element that may have been involved ; and each time the element has the ability to stop the propagation.

In ECS, I would assume there is some kind of System that monitors whether or not something gets clicked?

Any best-practices here? Anything I misunderstood? (I imagine the "buttons" in the "main menu" I'm creating, to be some kind of clickable)

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Current status

• [ ] Rightclick-handling

[paked]

AFAIK there is no "Clicking Idiom" in ECS. @matiwinnetou correct me if I am wrong.

Clicking is something we desperately need though, I am a big fan of the propagation model from javascript/html though.

Would you mind if I took this PR?

[EtienneBruines]

Be my guest. :+1:

[paked]

@EtienneBruines what are your thoughts on implementing this handler at the World level?

[EtienneBruines]

A ClickSystem, together with ClickComponents.

If an Entity has a ClickComponent, the ClickSystem will use the SpaceComponent and Mouse values to see if it's being clicked, and if so, either set some value at ClickComponent to CLICKED, or perhaps dispatch some Message?

Misread your message. At the World level... hmm. They'd have to register some kind of OnClick event, but who should do that? Systems could do that, I guess.

Or just dispatch a Message, and then everyone can Listen for those messages if he/she pleases?

[paked]

@EtienneBruines I think implementing this as a System is a good idea. Although, if we do this we may as well remodel the way key input works as well.

I believe going with the messaging model for this would serve us best.

[EtienneBruines]

Well, with keys the state is kinda important: just clicked, holded, released, etc. And combinations of keys.

A click is simply a click.

[paked]

@EtienneBruines state can actually be important for clicks too.

Imagine a button: You want to act when the button has been released!

Imagine a shooting game: You want to act when the button is first pressed, and perhaps when it is continuously held down.

Either way however, this is irrelevant (for both clicks and key presses). Data can be transferred within a message which could be used to contain the state.

For example

engi.Mailbox.Listen("ScoreMessage", func(message engi.Message) {
    scoreMessage, isScore := message.(ScoreMessage)
    if !isScore {
        return
    }

    sc.scoreLock.Lock()
    if scoreMessage.Player != 1 {
        sc.PlayerOneScore += 1
    } else {
        sc.PlayerTwoScore += 1
    }

    log.Println("The score is now", sc.PlayerOneScore, "vs", sc.PlayerTwoScore)

    sc.upToDate = false
    sc.scoreLock.Unlock()
})

[EtienneBruines]

Good point. Messages are kinda cheap anyway, so we could do that, yes.

[paked]

Thoughts @matiwinnetou?

[EtienneBruines]

(We should also note that this should indeed also cover things like hover)

[EtienneBruines]

Have you already started working on this, or can I create something with a ClickSystem and ClickComponent, which has some states (i.e. Clicked, Hovered, Focused, etc.)?

(I'm making a little game, and am in need of this; don't want to rush you, but also don't want to wait if you don't have time for it anyway; again: I do not mean this in a negative way, whatsoever. :smile: )

[paked]

@EtienneBruines feel free to take this.

[EtienneBruines]

Tricky; currently at "how to handle zooming", and "how to handle scrolling to the sides".

The very basics work.

[paked]

:+1:

On Fri, Nov 27, 2015 at 8:20 AM Etienne Bruines notifications@github.com wrote:

Tricky; currently at "how to handle zooming", and "how to handle scrolling to the sides".

The very basics work.

— Reply to this email directly or view it on GitHub https://github.com/paked/engi/issues/59#issuecomment-159995290.

[EtienneBruines]

Current status:

TODO

• [ ] Rightclick.

[faide]

Etienne, Paked,

I am using the current head from paked/engi and I am using the MouseSystem and MouseComponent to handle clicks on a HUD entity of mine.

At the moment I note that the mouse component does not give me access to the "Mouse Released" event. If I try to use the mc.Clicked against my entity I receive a lot of events (I assume this is normal because my poor fingers are not quick enough to compete against 120fps...) and I'd like to receive only one because each click will launch actions and cost resources. I can (and did) implement some kind of filter based on timing but I find it brittle and error prone.

I would like to make the "mouse released inside your entity" available through the MouseComponent as mc.Released. I don't see the big picture yet so it is possible this event does not make a lot of sense and a better solution already exists... please just let me know if this is the case.

What do you think of it? If you are interested I'll propose a PR.

BTW I added to this issue instead of opening a new one because of the "click system" focus of my question

[paked]

@faide If you want to take a crack at this, I'd be happy to review the pull request!

[faide]

@paked I did first run here: #146

[paked]

Correct me if I'm wrong, but #146 fixed this.