Linked by Thom Holwerda on Sat 23rd Dec 2006 00:48 UTC, submitted by dumbkiwi
KDE This is a response to the article yesterday on the progress of GNOME and KDE. Aaron Seigo, a lead KDE developer, sets out the current state of progress with KDE 4, pointing out that KDE 4 is on track for a release in mid 2007. "Thom points to a quote from me that our goal is to have a 4.0 ready sometime in the first half of next year. That gives us until sometime in June and I'm still thinking we can make it."
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RE[4]: A lot of crap on that blog
by rayiner on Sun 24th Dec 2006 16:19 UTC in reply to "RE[3]: A lot of crap on that blog"
rayiner
Member since:
2005-07-06

I followed this discussion and while I understand that Vista has access to some pixel shaders that are trickier to use under Linux, I do wonder how much those pixel shaders are used by Vista, and how much more they bring.

Pixel shaders are at the core of Vista's 2D rendering architecture. When Avalon renders a path on the screen, it does not tesselate it to triangles then use the GPU to render the triangles. Instead, it draws a polygon that covers the projection of the path, and uses a pixel shader to fill in the regions that are inside the path, ignore the pixels that are outside the path, and anti-alias regions that are on the edge of the path.

This allows them to achieve very high-quality coverage-based anti-aliasing without having to use any full-scene anti-aliasing in the scene itself. That's a huge win because because even 16xFSAA (which itself incurs a huge memory cost and is only even supported on the latest cards) can't touch the quality of a good coverage-based anti-aliasing system like the one in Cairo's software renderer.

Without pixel shaders, using the GPU for rendering while maintaining quality becomes a rather difficult exercise. Basically, you either just punt and do everything in software (what Cairo currently does on AIGLX), or you use OpenGL only very late in the pipeline (what XGL does), thus giving up a lot of the potential benefit of using the GPU.

Note that this point doesn't just apply to pixel shaders. What happens when GPU's get advanced enough where you can just up an run most of pixman (Cairo's software renderer) on the coprocessor? How are you going to facillitate THAT through XRENDER?

The difference between Vista and Linux's stack as it stands today is the difference between OS X Jaguar and Vista. It's the difference between using the GPU just for some desktop effects, versus leveraging the GPU for the whole graphics pipeline. You can get a very good desktop with just the former (GNOME + Compiz is a VERY good desktop), but you're also giving up a ton of potential (and not to mention losing the feature war).

Edited 2006-12-24 16:29

Reply Parent Score: 4

archiesteel Member since:
2005-07-02

You can get a very good desktop with just the former (GNOME + Compiz is a VERY good desktop), but you're also giving up a ton of potential (and not to mention losing the feature war).

I understand this, however what I'm really curious about is how Vista will take advantage of this technological edge to implement such features. In other words, it's all fine and dandy to have a more powerful stack, but are they really using it to its potential? From what I've seen of Vista, it doesn't seem as if users will notice that much difference between it and, say, a Beryl-enhanced desktop.

To make a game console analogy: both the Xbox 360 and the PS3 are more powerful than the Wii, but the Wii's the one who is the most innovative, and the one that has generated the most buzz. While Vista has the technological edge (for a year or two), movies of it have yet to provide the "wow" factor that I get when I showcase my Beryl-enhanced laptop (which, I have to say, has a cheap 128MB integrated ATI card - nothing to get excited about, and yet I get very good performance...)

BTW, you seem very knowledgeable on this...I have to wonder, are you collaborating in any way to help improve the FOSS stack? It seems to me the *nix world would greatly benefit from someone like you working on such a project...

Reply Parent Score: 2