Red screen on launch

[camelid]

For every site, when I load it, a red screen is shown for several seconds. (Same with local test HTML files.)

Here's what it looks like:

@jdm thinks this is because of #25853 and at some point the OpenGL surface is cleared to red.

[camelid]

Could this line where we set clear_color in RendererOptions be related to the issue? It's set to None, and perhaps when it's later used the default in OpenGL is red.

servo/components/servo/lib.rs

Line 435 in 343f249

clear_color: None,

[camelid]

Nope. I tried changing it to ColorF::WHITE, but I still got the red screen.

[camelid]

@jdm Do you think this is an issue with Servo or with WebRender?

[jdm]

I'm pretty sure it's an issue with Servo.

[camelid]

Okay, thanks. I've been looking through the code in this repo and in surfman's, but I'm having trouble finding where surfaces are created. Could you point me to the spot(s) in Servo where they're created? Thanks!

[jdm]

https://github.com/servo/servo/blob/master/components/webrender_surfman/lib.rs#L56 is called from

servo/ports/glutin/headed_window.rs

Lines 147 to 158 in 343f249

	// Initialize surfman
	let connection = Connection::from_winit_window(&winit_window).expect("Failed to create connection");
	let adapter = connection.create_adapter().expect("Failed to create adapter");
	let native_widget = connection
	.create_native_widget_from_winit_window(&winit_window)
	.expect("Failed to create native widget");
	let surface_type = SurfaceType::Widget { native_widget };
	let webrender_surfman = WebrenderSurfman::create(
	&connection,
	&adapter,
	surface_type,
	).expect("Failed to create WR surfman");

.

[camelid]

Cool, thanks!

[Darkspirit]

Maybe related to #26353.

[camelid]

Although it seems in that one that nothing ever rendered, whereas this issue is that on startup there's a red screen and then the page is rendered.

[camelid]

Tried adding the code from

https://github.com/servo/servo/blame/9dbc6554f087ca3675104fb1bac45b0c442a0158/ports/glutin/headed_window.rs#L191-L193

to

servo/components/servo/lib.rs

Line 374 in d08c4ff

at @asajeffrey's recommendation, but still the red screen.

EDIT: GitHub doesn't seem to render two snippets in the same comment, so here's the first snippet copied-and-pasted:

        gl.clear_color(0.6, 0.6, 0.6, 1.0);
        gl.clear(gl::COLOR_BUFFER_BIT);
        gl.finish();

[camelid]

@jdm is this an issue only on macOS or on Linux/Windows too?

[atouchet]

I do not see this issue using Windows 10.

[camelid]

Huh, interesting. Thanks for the info!

@asajeffrey Perhaps this is an issue with surfman's platform-specific APIs then?

[camelid]

I just tried a prebuilt Servo binary on my Ubuntu VM and it worked fine without the red screen.

[camelid]

Likely an issue with the platform specific background code, e.g. surfman, winit. Needs more experimentation.

[camelid]

I tried running the chaos_game example in surfman, but no red screen - it worked fine.

I'm guessing the red screen is either caused by winit or the way servo calls winit or surfman.