Everything is super dark in epiphany

[Barugon]

Describe the bug
The demo web app is super dark in epiphany. See screenshot below.

To Reproduce
Steps to reproduce the behavior:

1. Open the demo web app in epiphany.

Expected behavior
Should look like it does in other web browsers (e.g. Firefox).

Screenshots

Desktop (please complete the following information):

• OS: Fedora 34
• Browser: Epiphany
• Version: 40.3

[KentaTheBugMaker]

It seems to me using wrong surface format.
It occurs when surface format is not SRGB.

[Barugon]

Maybe linear RGB?

[KentaTheBugMaker]

when i wrote vulkano backend it suffers color glitch on UNORM not on SRGB .
maybe your web backend painter is WebGL1?

[KentaTheBugMaker]

I tested webgl 1 with Srgb Texture support .
It does not color glitch.
your browser maybe don't support Srgb texture.

[KentaTheBugMaker]

you need to test your browser and hardware by accessing to below.
https://webglreport.com/
and write your hardware.

[Barugon]

Here's the result. WebGL 2 is not supported.

[KentaTheBugMaker]

this site don't report GPU name correctly so we must determine your hardware more.
it show me EXT_sRGB is supported but bad result maybe crappy WebGL implementation?

[Barugon]

It's a Radeon RX 5700 XT using the open source drivers.

[KentaTheBugMaker]

I think webkitGTK problem not egui or gfx driver.
or other gpu on your system selected?

[Barugon]

No other GPU.

[KentaTheBugMaker]

servo does not support webGL2 and EXT_sRGB but render it correctly.
I think webkitGTK present EXT_sRGB but actual frame buffer is not sRGB


.

[emilk]

Perhaps we can use navigator.userAgent to special-case epiphany in the srgb_supported check in https://github.com/emilk/egui/blob/master/egui_web/src/webgl1.rs#L65 ?

[KentaTheBugMaker]

I fixed it by reapply sRGB correcting in post process
I will make PR to fix this problem.

[KentaTheBugMaker]

I found midori also have this issue.
so I generalized to WebKitGTK.