After a bit of searching I came across Xgl, it is an X serverwhich is layered on top of OpenGL and because of this, it canaccelerate drawing operations on the desktop. Xgl takes advantage ofthe processing power available in modern graphics cards by usingtheir OpenGL drivers to hardware accelerate X, OpenGL and Xvideoapplications. In general terms, think of the processing which is putinto rendering frames in 3D games and then using that capability torender the humble desktop. What this means is that you getnoticeably fast rendering anti-aliased fonts and can performintricate graphical calculations far faster than other X serverswithout OpenGL.
What this means for day to day usage is that when a window ismoved around, you can set it up so that the window animates whilemoving. You can also change window transparencies on the fly, say forexample I was writing a report in OO and wanted to briefly check thescore for a football match, I can just increase the transparency ofthe present window allowing me to view the window beneath. Note thatthis transparency is not application specific, it is due to Xgl'sgraphic rendering capabilities that this is possible.
Low Resolution Video
High Resolution Video
A handy feature which will be a boon to those with poor eyesightor those who visit sites which display content using different fontsizes is the zoom function. Presently, you either have to increasethe font sizes using your browser's control or downgrade to a lowerresolution or worst case install larger fonts. With an Xgl enableddesktop one has the ability to zoom into a particular section whileleaving the rest of the X session at the normal resolution and zoom.
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High Resolution Video
Perhaps the most talked about feature of an Xgl enabled desktop isthe desktop cube. Most people can visualize the virtual desktopavailable in most OS's (yes even Windows XP has this), the cube isjust an extension of this. Instead of having a row of icons fromwhich you select which desktop you want to go to, with a Xgl enabledX-Sever, you can "drag" the next desktop onto the screen.This dragging action is not just restricted to one direction, but inall directions. I know it doesn't sound like much, other than moreeye candy to eat up system resources, but personally I like it.Please note that the videos uploaded with this article may show jerkymotion, but in reality, the motion is smooth.
Low Resolution Video of Outer Cube
High Resolution Video of Outer Cube
Low Resolution Video of Inner Cube
High Resolution Video of Inner Cube
At the moment, Xgl must be used together with a compositor/windowmanager in order to exhibit all of its capabilities. The presentlyavailable compositor utility, which was developed in conjunction withXgl is Compiz. Compiz runs on top of the DE and provides the fancyanimations i.e. transparency, cube, zoom etc. At the time of writingXgl/Compiz works quite well with Gnome and XFCE. According to KDE website, KDE support is still under development and should be readysoon.
Some of you may be wondering what kind of system will be requiredto run this? Well, I tried it on 3 different computers by means ofthe Kororaa live cd (see below). Their relevant specs are as follows-
System 1(Desktop): AMD Athlon XP 1800
512 MB DDR RAM
32 MB GeForce 2 Integratedgraphics
System 2 (Laptop): IntelMobile Pentium 4 3.2 GHz HT
512 MB DDR RAM(Dual Channel)
64 MB Mobility Radeon 9700 Prographics
System 3 (Desktop): AMD Athlon 643000
1024 MB DDR RAM (Dual Channel)
128 MB RadeonX300 PCI-E graphics
Yes, the Radeon's do run with 3D support with fglrx drivers,glxgears gives ~500 fps for the 9700 Pro, ~350fps for the X300 infull screen at a resolution of 1024x768 and ~55 fps for the GeForce2. See herefor a list of supported and unsupported cards. I also tried it on aworkhorse Pentium 3 733 computer, sadly as I expected, Kororaa didn'tload as the i810 graphics chip that the computer uses isn'tsupported.
As I mentioned before, Xgl is quite a memory hog. At any giveninstant, it is using ~50MB of RAM and while creating the flash videosuploaded with this article, the vast majority of swap space availableon my hard drive was swallowed up (A first for me since I have beenrunning on 2.6 kernels). On system's 2 and 3, the fancy animationswere smooth and rendered perfectly, however on system 1, there was aslight lag in rendering the animations which became more pronouncedas videos were created and as more applications were loaded up. Nodoubt this was due to the combination of using a live cd and outdatedgraphics chipset. Since I have a policy of not messing with my systemtoo much during semester, I can't say for sure how these computerswill perform had Xgl been natively installed i.e. not running off alive cd.
I am guessing that you may be wondering how you can also try this,or which distro has this kind of features enabled. There are a fewdistros which have Xgl either in their upcoming releases or in theirpackage repositories. Below are the distros which either have Xgl intheir repositories or will have an upcoming release which supportsthis:
* Fedora Core 5, Fedora doesn't use Xgl per se, rather it uses AIGLXwhich provides the same functionality. The reason behind this wasthat during a part of the development time for Xgl, it was closedsource in order to get it ready quickly. You can read more about ithere
* SUSE 10.1, due to be released April 13th2006. You can install Xgl on prior versions of SUSE, for more infosee thispage
* Gentoo, Xgl is available in Portage's maskedpackages, see the GentooWiki for more info.
* Arch Linux has it available in itsrepositories. See herefor more info.
* Mandriva presently doesn't support Xgl,however they have provided thishowto to get it running.
* Ubuntu is rumored to provide it in its nextupdate Dapper Drake
For those of you still undecided about whether to upgrade to Xgl,I suggest you try out a live cd by the name of Kororaa.Kororaa is a Gentoo based live cd compiled for i686 class machines,it comes with Gnome, Firefox and some media players, most importantlyit comes with Xgl enabled. I experienced some problems runningKororaa on the AMD 64 system, due to the X300 card and the atidrivers present on the cd. I experienced random lockups during use,this issue can be fixed by using the latest fglrx drivers, or bywaiting for the next release of the Kororaa live cd.
Some people may be thinking, what is the use of all this, I meanit is just more eye candy which will eat up precious systemresources. That may be true, but looking to the future it is easilyseen that an increasing number of OS's will move to a more 3D likeplatform, so if there was a unified 2D/3D rendering engine there willbe a smaller codebase from which the graphical system is controlled.It also removes all driver-dependent code from the X server itself,and allows for accelerated Compose and Render operations which areneeded for transparent windows to be independent of the graphicsdriver.
In conclusion, Xgl is an exciting technology, it still needs somework to be done mainly to do with non nvidia/ati graphics cards andextending support to a wider variety of graphics chipsets. I for onewill wait a bit longer (until the holidays) before attempting toinstall it onto my computer, perhaps by then more animations/pluginswill be made available and support for other DE's would be available..