2012124 - pointermove movementY is always zero in requestPointerLock mode

Status: RESOLVED DUPLICATE of bug 2036028

(Core :: DOM: Events, defect, P3)

Description

[caiiiycuk]

Attachment: ffbug.mp4

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:146.0) Gecko/20100101 Firefox/146.0

Steps to reproduce:

1. I am able to reproduce it with this:

target.addEventListener("pointerdown", (e) => target.requestPointerLock({ unadjustedMovement: true }));
target.addEventListener("pointermove", (e) => {
    console.log(e.movementX, e.movementY);
});

Slowly move mouse up

2. Or this testcase from here (https://bugzilla.mozilla.org/show_bug.cgi?id=1895796)

Open https://codepen.io/gensee/full/zYQOXLK, lock mouse and move it

Actual results:

1. The output is 90% zero (i am moving constantly), and sometimes there are +1 -1, cumulative value is zero. This prevents me to play games on different websites using FF.

2. My Y coordinates changes is zero (chrome works fine look at the video).

Expected results:

1. I should see sequences of +1 or -1.

2. y should change

Comment 1

[caiiiycuk]

Distributor ID: Ubuntu
Description: Ubuntu 25.10
Release: 25.10
plasmashell 6.4.5
wayland

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::DOM: Events' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 3

[Olli Pettay [:smaug][[e-mail]]]

masayuki, you looked at some movementX/Y stuff recently. Does this bug ring any bells?

Comment 4

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

(Today, I was PTO-ish due to a private matter so that I've not investigated this yet.)

I didn't change the logic at least intentionally. So, I have no idea and I'm not familiar with Pointer Lock implementation.

Edgar, how about you?

Comment 5

[Edgar Chen [:edgar] (OOO ~ 07/13, 07/16 ~ 07/20)]

I will take a look.

Comment 6

[Edgar Chen [:edgar] (OOO ~ 07/13, 07/16 ~ 07/20)]

I can reproduce this on Wayland and only happens on OOP iframe. If the pointerlock request is on the top-level document, I can not reproduce the issue, e.g. https://mdn.github.io/dom-examples/pointer-lock/. I think this is Wayland specific issue. And I guess this is something related to https://searchfox.org/firefox-main/rev/eea0f8f080f0eb810c0c6296da9792e81cd69ce6/widget/gtk/nsWindow.cpp#9633-9635. Taking this to see now.

Comment 7

[Edgar Chen [:edgar] (OOO ~ 07/13, 07/16 ~ 07/20)]

I believe bug 2036028 also fixes this. Feel free to reopen or file a new bug if you still encounter same issue.