web: Input is broken on international or non-qwerty keyboard layouts

[rparrett]

This is due to a workaround for an issue that was causing the backspace key to be super janky. That issue may be in bevy and/or winit.

taipo/src/typing.rs

Lines 400 to 413 in ebcffca

	// We were previously using Res<Events<ReceivedCharacter>> to handle the ascii bits,
	// and Res<Events<KeyboardInput>> to handle backspace/enter, but there was something
	// wacky going on where backspace could end up coming in out of order.
	//
	// After testing using puppeteer to shove various keyboard inputs in, it seems like
	// this solution, though ugly, results in a better typing experience.
	//
	// I had also attempted to get ReceivedCharacter to give me backspace/enter, but that
	// was not working, despite winit docs seeming to suggest that it should. But I found
	// that I received no ReceivedCharacter events at all when typing backspace/enter.
	//
	// I'm guessing that the ReceivedCharacter approach would be ideal though if this
	// solution doesn't work for people with non-english keyboards or dvorak layouts or
	// whatever.

[rparrett]

The answer is probably in here somewhere: rust-windowing/winit#1806

[rparrett]

enter/backspace seem to produce ReceivedCharacter events in non-web scenarios (running the bevy "char_input_events" example) but not in this game / in wasm builds.

typing_system should be as simple as this, but it just does not work.

#[derive(Default)]
pub struct ReceivedCharacterState {
    event_reader: EventReader<ReceivedCharacter>,
}
fn typing_system(
    mut typing_state: ResMut<TypingState>,
    mut state: Local<ReceivedCharacterState>,
    char_input_events: Res<Events<ReceivedCharacter>>,
) {
    for event in state.event_reader.iter(&char_input_events) {
        info!("{:?}", event.char);
        if event.char == '\u{7f}' {
            typing_state.buf.pop();
        } else if event.char == '\r' {
            let text = typing_state.buf.clone();

            typing_state.buf.clear();
            typing_submit_events.send(TypingSubmitEvent { text });
        } else {
            typing_state.buf.push(event.char);
        }
    }
}

As far as I can tell, bevy_winit just passes ReceivedCharacter events straight through from winit, so it seems like it must be a winit issue.

[rparrett]

It appears at a glance that winit just passes along keypress events.

https://developer.mozilla.org/en-US/docs/Web/API/Document/keypress_event

And while enter works in that example, backspace does not. (Chrome)

So that angle seems pretty hopeless.

However, it looks like KeyBoardInputEvent has a scan_code property that we could be using instead of key_code. When cast as a char, this seems to produce the correct letters when typing qwertz with a qwertz layout.

I am not actually sure what this "scan code" is though, and the results when typing punctuation seem mysterious. (particularly - which we need.)

[rparrett]

Blocked on rust-windowing/winit#1888

[rparrett]

Just checked on this again, and winit (main branch) is still using keypress, and backspace is still not being passed along.

If we want to support non-qwerty layouts right now, it probably needs to be by allowing the user to choose the layout in a settings menu.

[rparrett]

Fixed! It's now possible to get character data form Bevy's EventReader<KeyboardInput>. We still can't use ReceivedCharacter due to inconsistencies with backspace between web/native builds.