1609908 - Canvas resize aspect ratio wrong in nightly with webrender

Status: VERIFIED FIXED

(Core :: Graphics: CanvasWebGL, defect, P1)

Description

[julien_sosthene]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:74.0) Gecko/20100101 Firefox/74.0

Steps to reproduce:

Open a webpage with a 3D canvas (WebGL context) on nightly, and resize the page dynamically.

Test page : https://threejs.org/examples/#webgl_materials_standard

(Setup: Nightly on Windows 10, Nvidia RTX 2060 card, And Preview Nightly on Android 10, OnePlus 6)

Actual results:

The content of the canvas, which previously resized correctly, now renders on a streched zone instead of adapting the ratio as it used to.

The size of the canvas is OK, but the rendered portion is stretched. It looks like a size setting problem, or more likely a problem when someone sets the webgl context viewport.

This bug happens on Desktop Nightly and on Preview Nighlty but not on regular stable-branch Firefox.

Expected results:

The aspect ratio of the drawn area should have adapted to the new canvas size.

(See stable Firefox or Chrome to compare)

Comment 1

[Simona Badau, Desktop QA]

I could not reproduce this issue - when loading the provided link, I get a crash on the latest Nightly 74.0a1 (Bug 1608311). I'm going to set the component Canvas: WebGL so that someone with more knowledge in this area will take a look over this.

Comment 2

[Patrick (he/him)]

Able to reproduce this issue in Nightly 74.0a1 (2020-01-21), but not Beta 73.0b7 on Windows 10.

Comment 3

[Patrick (he/him)]

Cannot reproduce this issue in a fresh profile in Nightly build 20200121215203.

Comment 4

[Patrick (he/him)]

Attachment: prefs.js for impacted profile

For the issue to be reproduced, this prefs.js file needs to be copied into the profile.

Comment 5

[Timothy Nikkel (:tnikkel)]

The only thing you need from the prefs file is to enable webrender.

Comment 6

[Timothy Nikkel (:tnikkel)]

Regression range

https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=5cbf5bb11c585d69321b420f67ffb62544141427&tochange=e1b0906509efa6433978b9f980ec639b7eafbc6d

-> bug 1477756

Comment 8

[Kelsey Gilbert [:jgilbert]]

Zooming also causes letterboxing, so I suspect a compositing interaction, not a glViewport issue.

Comment 9

[Kelsey Gilbert [:jgilbert]]

We never set mResetLayer = true like we used to, so WebRender thinks it's the same size as ever.

Comment 10

[Kelsey Gilbert [:jgilbert]]

We should write a reftest.

Comment 11

[Kelsey Gilbert [:jgilbert]]

Attachment: Bug 1609908 - Reset WebGL layer on resize.

Comment 13

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/8c876eb8651e
Reset WebGL layer on resize. r=lsalzman

Comment 14

[Razvan Maries]

https://hg.mozilla.org/mozilla-central/rev/8c876eb8651e

Comment 15

[Patrick (he/him)]

Able to reproduce this issue in Nightly 74.0a1 (2020-01-17). No longer able to reproduce in 74.0a1 (2020-01-24). All tests performed in Windows 10.