Swipe input not working?

[GrimLothar]

I followed the documentation to enable all the inputs on my game, but although arrows work fine, swiping on a phone doesn't seem to be doing anything...

I have this

        initInput()

            onInput(['arrowleft', 'swipeleft', 'dpadleft'], () => {
                player.playAnimation('walk_left');
                player.resetCollisionBox()
                player.collisionBox.x -= 64
                // don't move the player if he collides with the collision layer
                if (tileEngine.layerCollidesWith('blocks', player.collisionBox)) {
                    return;
                }

                player.x -= player.width;
            });

I also tried adding this:

      initPointer();
        initGesture();

but swiping is still not working

[straker]

I can take a look at it later today and see if I can spot anything.

[straker]

So I tested out a basic example and swipe gestures seem to be working for me. I have an android phone so I'm unable to test iOS though.

import kontra from '/src/kontra.defaults.js';

(async () => {
  kontra.init();
  kontra.initInput();

  const sprite = kontra.Sprite({
    x: 100,
    y: 100,
    color: 'red',
    width: 40,
    height: 40
  });

  kontra.onInput(['arrowleft', 'swipeleft', 'dpadleft'], () => {
    sprite.x -= sprite.width;
  });

  kontra.onInput(['arrowright', 'swiperight', 'dpadright'], () => {
    sprite.x += sprite.width;
  });

  kontra.GameLoop({
    render() {
      sprite.render();
    }
  }).start();
})();

[GrimLothar]

Aha I have an iPhone myself... ok, Will try your example tomorrow and get back to you. If it doesn't work it's def an iOS issue... happy to look into it if you tell me where to look in the source code!

[GrimLothar]

yeah... that example you shared is not working on iOS :(

[straker]

Well dang. I don't have any good way to look into that.

[sylfel]

Hi straker
I try to understand why it's not working on iOs phone, and i may found something :

It's also not working in Firefox adaptive view ! (easier to test)

in Gesture.js there is a test :

kontra/src/gesture.js

Lines 135 to 142 in ae63cba

	// ensure that the indices of touches goes from 0..N.
	// otherwise a length 1 touch could have an index of 2
	// which means there were two other touches that started
	// a gesture
	// @see https://stackoverflow.com/a/33352604/2124254
	[...Array(touches.length).keys()].every(
	key => touches[key]
	) &&

This "key" corresponding to identifier in Touch object
In webkit, it's 0 for first touch, 1 for second, and in next movement, it restart to 0 for first touch, 0 and 1 if there's two touches...
but in firefox (and i suppose in safari) it's an incremental
So, first movement, it's 0 for first touch, 1 for second touch
in second movement, it's 2 for first touch ...

So test doesn't work.

Question : How to correct this ? if you have an idea, i can try a PR.
I may drop this test, but if it's here, it may be usefull, isn't it ?

[straker]

@sylfel interesting find. I'll have to think about how to handle touches that way. Probably just need to make sure that a started touch also has an end so we don't skip one on accident.