You can't override the "escape" key firing a quit event

[icefoxen]

I thought you could but it turns out not. This should be fixed; you can ignore or handle the quit event, but there's no way to make pressing "escape" not fire it.

[icefoxen]

We... can't actually make EventHandler::key_down_event() call Context::quit() by default because it never has access to a Context.

So far it seems the only sensible thing is to remove this feature entirely and make sure the tutorials have a key_down_event() handler to handle escape button presses.

[icefoxen]

IT'S EVEN WORSE because key_down_event() doesn't get a Context either, so it can't call Context::quit().

When I wrote EventHandler I couldn't think of any use case that would need the Context: most operations you need it for are expensive things like creating resources, which are best done outside event handlers, or things like drawing which have their own event. However, we are slowly accumulating more options to mess around with the game/window state, like graphics::set_mode(), and accessing those needs the Context.

So it seems like the Right Thing might be to update the EventHandler trait to pass the Context to the event callbacks as well, however that is a breaking change so would have to wait for 0.4.

[obsoke]

I agree that this is the right change to make; otherwise, you are left setting flags from the event handling methods to then act upon in update. Better to just act directly, IMO.

In a similar vein, what about arguments passed to update such as dt? Would those be useful in other methods? e.g.: From key_down_event, some other method would be called when Space is held down to do something like speed * dt to move a character.
Or perhaps being able to get a Duration object from the Context representing the current delta time would be a cleaner alternative to passing an additional argument to each of the EventHandler methods.

[icefoxen]

Eeeeeeh. I'm wary of passing dt to event handlers because the Right Way is almost always to do as little as possible in event handlers besides register that events happened. Getting a Duration from the context isn't a terrible idea though...

[Manghi]

@obsoke Small tidbit: the way I avoided this was to set a flag which would detect if a key was already pressed.

For a small menu system which has an option to exit the game, I had to manually call Context::quit() that way. Wasn't that big of deal, but it sounds like its not the best method??

[rofrol]

@icefoxen Maybe add to 0.4 milestone?

[icefoxen]

Oops, thought I had already.

[Manghi]

@icefoxen You mentioned that you could ignore the Context::quit()-from-ESC-key event in your first post.

How exactly would this be done?

[icefoxen]

Override the quit_event method on your EventHandler and have it check whether the escape key is pressed, exactly like you said. If the quit_event method returns true, the game does not exit.

[Manghi]

quit_event, so obvious. Thanks! Works like a charm.

[icefoxen]

DONE! \o/