> It's funny that in one paragraph you talk about how optional extensions are great and then in the next paragraph you blame OpenGL for optional extensions.
I'm not blaming OpenGL, I'm just telling that it's not easier to use than XRender.
> SNA does not work anywhere except for i965 hardware. So it's kinda irrelevant. Besides, it's only used to implement XRender.
You're wrong here. Check http://www.x.org/wiki/IntelGraphicsDriver at least. But I wasn't asking where it works, I was asking why it works faster on the same hardware. Hint: because it uses hardware-specific optimisations for 2D rendering, impossible outside of the driver, impossible in Wayland.
> Nope. Wayland simply doesn't need it.
That universal excuse "I don't need it"... Wayland doesn't need anything. It just makes optimised 2D interface impossible, and it does not care that almost everything in modern interface is 2D.
> That used to be true 5 years ago. Now OpenGL standards mandate the required extension sets
And new extensions appear... So the problem is still there.
> BTW, how can I check that a certain feature of XRender is accelerated?
You don't need to check that. That's the beauty of XRender. You only need to check that it's supported. And it is supported for 10+ years.
Acceleration is up to the driver. To make sure if it's really accelerated you have to benchmark it. That applies to both GL and XRender. Because on some drivers/hardware some "accelerated" features actually work slower than software rendering.
Posted Mar 20, 2013 15:07 UTC (Wed) by Cyberax (✭ supporter ✭, #52523)
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> I'm not blaming OpenGL, I'm just telling that it's not easier to use than XRender.
Is it? OpenGL now has very nice wrappers that can abstract gritty details.
> You're wrong here. Check http://www.x.org/wiki/IntelGraphicsDriver at least. But I wasn't asking where it works, I was asking why it works faster on the same hardware. Hint: because it uses hardware-specific optimisations for 2D rendering, impossible outside of the driver, impossible in Wayland.
That's incorrect. You can use whatever rendering API you want, the only requirement is that you use a surface that can be composited by Wayland.
Nobody stops you from using driver-specific rendering methods.
I've actually checked the SNA source code and it looks like it's using the regular GEM and command submission system of the kernel driver. So you definitely can use something like it for 2D rendering with Wayland. You probably can even use the current SNA with Wayland.
>That universal excuse "I don't need it"... Wayland doesn't need anything. It just makes optimised 2D interface impossible, and it does not care that almost everything in modern interface is 2D.
Incorrect on both counts.
> You don't need to check that. That's the beauty of XRender. You only need to check that it's supported. And it is supported for 10+ years.
Yeah, sure. That's why many XRender-based apps are about as fast as molasses.
LCA: The ways of Wayland
Posted Mar 20, 2013 16:51 UTC (Wed) by Cyberax (✭ supporter ✭, #52523)
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> You're wrong here. Check http://www.x.org/wiki/IntelGraphicsDriver at least. But I wasn't asking where it works, I was asking why it works faster on the same hardware. Hint: because it uses hardware-specific optimisations for 2D rendering, impossible outside of the driver, impossible in Wayland.
Actually, running SNA on _Wayland_ is not only possible, but it works RIGHT NOW.
Posted Mar 20, 2013 17:14 UTC (Wed) by renox (subscriber, #23785)
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One point Cyberax :-)
I wonder why Serge is so hell bent in finding imaginary drawbacks of Wayland even though it's not difficult to find real "drawbacks" aka trade-off in Wayland.
The latest one I've read in Wayland mailing list: some weird screen have different subpixel ordering depending on the pixel position(!!), so as Wayland clients doesn't know where their window are going to be displayed, they cannot do subpixel aware rendering on these screen..
I hope that these kind of screen are rare, bleah.
LCA: The ways of Wayland
Posted Mar 20, 2013 17:23 UTC (Wed) by renox (subscriber, #23785)
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To be complete: someone has a plan to add an extension fix this, so this may change, sorry Serge ;-)
LCA: The ways of Wayland
Posted Mar 20, 2013 18:39 UTC (Wed) by chris.wilson (subscriber, #42619)
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Claiming that will be the same speed is stretching the truth by about a factor of 2.
LCA: The ways of Wayland
Posted Mar 20, 2013 18:48 UTC (Wed) by Cyberax (✭ supporter ✭, #52523)
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Well, yes. There's an additional roundtrip (from the X Server to the Wayland compositor). However, there are no reasons why it's not possible to do completely locally (perhaps using a better API like OpenVG).