Binary package “xlockmore-gl” in ubuntu karmic

Lock X11 display until password is entered -- GL version

 xlock locks the X server till the user enters his/her password at the
 keyboard. While xlock is running, all new server connections are
 refused. The mouse cursor is turned off. The screen is blanked and a
 changing pattern is put on the screen. If a key or a mouse button is
 pressed then the user is prompted for the password of the user who
 started xlock.
 This version is built with additional OpenGL and XPM modes. The
 companion package xlockmore does not contain them. This is the only
 difference between the two packages.