Bug 221638 – Report that SmashKarts is slow on iOS

• Status: NEW
• Component: WebGL

[Kenneth Russell]

In a meeting with the developers of https://www.smashkarts.io/ , they reported that the game has severe lag and other issues on iOS.

It would be great to test this with the latest WebKit builds including the ANGLE backend and WebGL 2.0 support and see how the game is performing.

[Kimmo Kinnunen]

Thanks for the report!

The game does not work in macOS nor with macOS + using iOS UA string. Would be easier to debug if it did.

The game works kind-of OK on iOS. During startup the frames are very janky until the game has run for a while. It's unclear if the source is something WebGL related or something audio related or resource loading related.

I did experience some audio corruption after few minutes of playing on iPhone 12, unclear what is the source.

[Tom Greenaway]

I've tested on an iPhone XS. It seems that the performance issues are not continuous but they do impact the UX considerably. For example, once inside the game the FPS becomes stable but then it can lag all of sudden which triggers issues in the multiplayer and makes the game uncompetitive to play on iOS. I wonder if it's a build up of memory pressure or a networking problem.

I also found that the performance is poor on the title screen as well.

[Kenneth Russell]

Hmm, the game runs in both Chrome Canary 90.0.4408.0 and Safari Technology Preview Release 119 (Safari 14.1, WebKit 15611.1.10.1) on my 2017 15" MacBook Pro - though I'm still running 10.15.7.

I wonder whether this game's affected by Unity's user-agent string parsing that breaks on macOS 11.

[Tom Greenaway]

The developer's reports were specifically for iOS.

For me the game runs fine in Chrome on macOS as well. So I'm not sure what issue Kimmo is seeing. Perhaps Kenneth is correct about the Unity user agent issue creating Kimmo's problem.

However the iOS performance issues for Safari seems independent of this.

[Radar WebKit Bug Importer]

<rdar://problem/74409172>