Camera Panning / Zooming mixed up when using iOS

Vr_Tech · September 3, 2020, 9:16pm

From this example

https://www.babylonjs-playground.com/#SRZRWV#1

If you try to pan or zoom sometimes it does all or sometime it’s glitching out.

Any solutions?

sebavan · September 4, 2020, 10:14am

I am sorry I can not repro it seems to work on my iPhone. What device are you using ? @Cedric could you try as well just in case ?

Cedric · September 4, 2020, 11:40am

Tested on iPhone11 with Safari without any trouble. Same question as @sebavan for the device/ios/safari version. Can you also try to do a video of what’s happening?

Vr_Tech · September 4, 2020, 4:30pm

It seems to have happened when using one finger scrolling then another one coming right up then it jitters like this.

iPhone X
iOS 13.2.3

Cedric · September 4, 2020, 4:40pm

I get it! I can repro in on my iphone. I think this is reproductible on Android as well.

sebavan · September 4, 2020, 5:48pm

Cool, looks like you are up to fix it @Cedric let me know if you need anything.

Cedric · September 8, 2020, 1:20pm

I can reproduce the issue when rotating the camera with 1 finger then adding a second one.
It seems related to this comment:

github.com

BabylonJS/Babylon.js/blob/1e3d153d295340931e2ae4d3d871d9f4760350c9/src/Cameras/Inputs/BaseCameraPointersInput.ts#L133


try {
    srcElement.releasePointerCapture(evt.pointerId);
} catch (e) {
    //Nothing to do with the error.
}

if (!isTouch) {
    this.pointB = null; // Mouse and pen are mono pointer
}

//would be better to use pointers.remove(evt.pointerId) for multitouch gestures,
//but emptying completely pointers collection is required to fix a bug on iPhone :
//when changing orientation while pinching camera,
//one pointer stay pressed forever if we don't release all pointers
//will be ok to put back pointers.remove(evt.pointerId); when iPhone bug corrected
if (engine._badOS) {
    this.pointA = this.pointB = null;
} else {
    //only remove the impacted pointer in case of multitouch allowing on most
    //platforms switching from rotate to zoom and pan seamlessly.
    if (this.pointB && this.pointA && this.pointA.pointerId == evt.pointerId) {

@sebavan or @Evgeni_Popov Do you know if this hack can be properly removed ?

sebavan · September 8, 2020, 1:42pm

I have no idea at all, but it is probably super old as I remember it always being here

You might try without on IoS and see what happens ? but it should not impact android at all which is pretty strange.

Cedric · September 8, 2020, 3:00pm

That bug seems to be fixed on iOS. But it doesn’t fix the jittering issue. I’m still trying to find a reliable way to reproduce it.

Vr_Tech · September 8, 2020, 7:18pm

I was experimenting with three.js, they seem using active fingers to determine the behaviors.

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Camera Panning / Zooming mixed up when using iOS

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