Linux Bible. Christopher Negus
Adding 3D effects with AIGLX
Several initiatives have made strides in recent years to bring 3D desktop effects to Linux. Ubuntu, openSUSE, and Fedora used AIGLX (https://fedoraproject.org/wiki/RenderingProject/aiglx).
The goal of the Accelerated Indirect GLX project (AIGLX) is to add 3D effects to everyday desktop systems. It does this by implementing OpenGL (http://opengl.org) accelerated effects using the Mesa (http://www.mesa3d.org) open source OpenGL implementation.
Currently, AIGLX supports a limited set of video cards and implements only a few 3D effects, but it does offer some insight into the eye candy that is in the works.
If your video card was properly detected and configured, you may be able simply to turn on the Desktop Effects feature to see the effects that have been implemented so far. To turn on Desktop Effects, select System ➪ Preferences ➪ Desktop Effects. When the Desktop Effects window appears, select Compiz. (If the selection is not available, install the compiz package.)
Enabling Compiz does the following:
Starts Compiz Stops the current window manager and starts the Compiz window manager.
Enables the Windows Wobble When Moved effect With this effect on, when you grab the title bar of the window to move it, the window wobbles as it moves. Menus and other items that open on the desktop also wobble.
Enables the Workspaces on a Cube effect Drag a window from the desktop to the right or the left, and the desktop rotates like a cube, with each of your desktop workspaces appearing as a side of that cube. Drop the window on the workspace where you want it to go. You can also click the Workspace Switcher applet in the bottom panel to rotate the cube to display different workspaces.
Other nice desktop effects result from using the Alt+Tab keys to tab among different running windows. As you press Alt+Tab, a thumbnail of each window scrolls across the screen as the window it represents is highlighted.
Figure 2.19 shows an example of a Compiz desktop with AIGLX enabled. The figure illustrates a web browser window being moved from one workspace to another as those workspaces rotate on a cube.
FIGURE 2.19 Rotate workspaces on a cube with AIGLX desktop effects enabled.
The following are some interesting effects that you can get with your 3D AIGLX desktop:
Spin cube Hold Ctrl+Alt keys and press the right and left arrow keys. The desktop cube spins to each successive workspace (forward or back).
Slowly rotate cube Hold the Ctrl+Alt keys, press and hold the left mouse button, and move the mouse around on the screen. The cube moves slowly with the mouse among the workspaces.
Scale and separate windows If your desktop is cluttered, hold Ctrl+Alt and press the up arrow key. Windows shrink down and separate on the desktop. Still holding Ctrl+Alt, use your arrow keys to highlight the window you want and release the keys to have that window come to the surface.
Tab through windows Hold the Alt key and press the Tab key. You will see reduced versions of all your windows in a strip in the middle of your screen, with the current window highlighted in the middle. Still holding the Alt key, press Tab or Shift+Tab to move forward or backward through the windows. Release the keys when the one you want is highlighted.
Scale and separate workspaces Hold Ctrl+Alt and press the down arrow key to see reduced images of the workspace shown on a strip. Still holding Ctrl+Alt, use the right and left arrow keys to move among the different workspaces. Release the keys when the workspace you want is highlighted.
Send current window to next workspace Hold Ctrl+Alt+Shift keys together and press the left and right arrow keys. The next workspace to the left or right, respectively, appears on the current desktop.
Slide windows around Press and hold the left mouse button on the window title bar, and then press the left, right, up, or down arrow key to slide the current window around on the screen.
If you get tired of wobbling windows and spinning cubes, you can easily turn off the AIGLX 3D effects and return to using Metacity as the window manager. Select System ➪ Preferences ➪ Desktop Effects again, and toggle off the Enable Desktop Effects button to turn off the feature.
If you have a supported video card but find that you cannot turn on the Desktop Effects, check that your X server started properly. In particular, make sure that your /etc/X11/xorg.conf file is properly configured. Make sure that dri and glx are loaded in the Module section. Also, add an extensions section anywhere in the file (typically at the end of the file) that appears as follows:
Section "extensions" Option "Composite" EndSection
Another option is to add the following line to the /etc/X11/xorg.conf file in the Device section:
Option "XAANoOffscreenPixmaps"
The XAANoOffscreenPixmaps option improves performance. Check your /var/log/Xorg.log file to make sure that DRI and AIGLX features were started correctly. The messages in that file can help you debug other problems as well.
Summary
The GNOME desktop environment has become the default desktop environment for many Linux systems, including Fedora and RHEL. The GNOME 3 desktop (now used in Fedora and RHEL 7 and RHEL 8) is a modern, elegant desktop, designed to match the types of interfaces available on many of today's mobile devices. The GNOME 2 desktop (used through RHEL 6) provides a more traditional desktop experience.
Besides GNOME desktops, you can try out other popular and useful desktop environments. The K Desktop Environment (KDE) offers many more bells and whistles than GNOME, and it is used by default in several Linux distributions. Netbooks and live CD distributions sometimes use the LXDE or Xfce desktops.
Now that you have a grasp of how to get and use a Linux desktop, it's time to start digging into the more professional administrative interfaces. Chapter 3, “Using the Shell,” introduces you to the Linux command-line shell interface.
Exercises
Use these exercises to test your skill in using a GNOME desktop. You can use either a GNOME 2.x (Red Hat Enterprise Linux up until RHEL 6.x) or GNOME 3.x (Fedora 16 or later or Ubuntu up to 11.10, or later using the Ubuntu GNOME project) desktop. If you are stuck, solutions to the tasks for both the GNOME 2 and GNOME 3 desktops are shown in Appendix B.
1 Obtain a Linux system with either a GNOME 2 or GNOME 3 desktop available. Start the system and log in to a GNOME desktop.
2 Launch the Firefox web browser and go to the GNOME home page (http://gnome.org).
3 Pick a background you like from the GNOME art site (http://gnome-look.org), download it to your Pictures folder, and select it as your current background.
4 Start a Nautilus File Manager window and move it to the second workspace on your desktop.
5 Find the image that you downloaded to use as your desktop background and open it in