Xgl
| Xgl
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 Compiz on Xgl with real transparency |
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| Basic data
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| Maintainer | David Reveman |
| Publishing year | 2006-01-02 |
| programming language | C. |
| category | Display server protocol |
| License | X11 license |
| freedesktop.org/.../Xgl | |
Xgl is an implementation of a display server for the X11 protocol. Xgl is based on the glitz program library to access the OpenGL API in order to run hardware accelerated. The project was in the early stages of development between 2006 and 2008 but was discontinued in June 2008.
Novell employee David Reveman announced the development of the Xgl architecture at the end of 2004. The source code was opened on January 2, 2006 and included in the freedesktop.org project. In the course of this, the developers made major changes to the program structure to make it easier to include additional graphics drivers .
Xgl should be on the Linux - Desktop additional effects such as transparency , shading or animations allow that the 3D functions of modern graphics cards without additional load on the processor to take advantage. Most modern PCs currently have sufficiently powerful graphics cards, but many manufacturers do not offer open source drivers for the supported platforms .
From a technical point of view, a window is started in a normal, classic X server in which OpenGL allows direct communication with the graphics card. This window behaves towards the window manager and other programs as the actual X server, similar to Xnest, for example . The output of the window is also what is output to the user on the screen.
Composition and window manager
In the course of the development of the Novell Linux Desktop 10, Compiz , the first experimental composition manager, was developed that demonstrates the new possibilities of Xgl. An important feature of Compiz is that, in addition to the compositing functionality, it also functions as a window manager . It currently replaces the corresponding window manager by default in a desktop environment. Sample applications such as transparency, 3D arrangement of virtual desktops, live preview of windows, stepless zooming and physical properties for windows (also known as the "wobbly" effect) are already implemented in Compiz, which demonstrate the possibilities of Xgl.
Other window managers were later expanded to include compositing functions that can also be used with Xgl. The Compiz cleavage Beryl can also be used with Xgl. In mid-2007, Beryl and Compiz were reunited. Beryl was renamed Compiz Fusion and abandoned the core of the project. Compiz Fusion now only provides plugins for Compiz (core component of the program).
Xglx
Xglx was the first back-end to be implemented for Xgl and is currently taking up most of the development work. It requires an already existing X server with GLX . In the future, however, Xgl will not run on an X server, but will have its own server implementation with Xegl.
Xegl
With Xegl there is a long-term goal in X development. Xegl is a server that writes directly to the frame buffer via OpenGL , using the Mesa 3D implementation of the EGL API .
At Xegl, all graphics should be displayed using OpenGL so that current graphics drivers can be designed more easily. These are currently split into individual parts for 2D and 3D acceleration, which would be omitted with such a simplification. Furthermore, all source code that is dependent on the graphics card driver is removed from the X server. The rendering of the server is independent of the X server.
Nvidia and ATI have signaled that in the event of a stable API, they would release binary drivers for OpenGL-based X servers.
Alternatives
With the AIGLX initiated by the Fedora project , there is another variant for Linux and other Unix platforms.
Hardware-accelerated 2D display is already included in macOS 10.4 under the name " Quartz 2D Extreme" . Windows Vista uses a similar technique.
Web links
- Novell: Xgl - release information, download, videos and screenshots etc. a.
- Announcement of Revemans on the X.Org mailing list (English)
- Xgl in the freedesktop.org wiki (English)
- Xegl in the freedesktop.org wiki (English)