NAME¶
OpenGL::XScreenSaver - prepare environment for writing OpenGL-based XScreenSaver
hacks
SYNOPSIS¶
use OpenGL qw(:all);
use OpenGL::XScreenSaver;
OpenGL::XScreenSaver::init();
# GetOptions(...); # parse your own options, if any
OpenGL::XScreenSaver::start();
while (1) {
glClear(...);
# draw your scene here
OpenGL::XScreenSaver::update();
}
DESCRIPTION¶
This module allows you to write OpenGL XScreenSaver hacks in Perl. It prepares
the GL to be used with XScreenSaver.
Read the synopsis for how your program might look.
Description of functions¶
The
init() function will return a true value if a
window to draw on has been found, and a false value if a window will have to
be created. This value can be ignored unless you want to make sure that your
screenhack cannot be executed outside XScreenSaver (e.g. if your standalone
version comes as an extra binary with keyboard control, which would be useless
in a screensaver).
The
start() function will open the connection to the
X server and bind to the window ID or create a new window to draw on (depends
on if it was called standalone or from XScreenSaver).
The
update() function should be called when you
finished rendering the frame. It will flush output and swap the buffers. In
the future it might also handle a minimal set of X events when run in
standalone mode (like window deletion requests by the window manager).
The
dimensions() function returns a list with the
width and the height of the currently used window.
About screenhacks¶
What follows is a short description of how it works and what XScreenSaver
expects a screenhack to do.
XScreenSaver tells the hack on startup what window ID the hack shall draw to.
This is either a small window mapping to the screen in the preview dialog, or
a fullscreen window. The window ID is passed either via the
-window-id
option or via the
XSCREENSAVER_WINDOW environment variable.
init() of this module checks both of these.
XScreenSaver handles all user input including exiting and pausing the
screensaver. The process is sent a SIGSTOP when the unlock screen is
displayed, obviously a SIGCONT when it is dismissed, and when the pointing
device is moved or the screen gets unlocked XScreenSaver sends a SIGTERM. This
means that no event handling is required by your screenhack whatsoever. This
again keeps the design of a screenhack dead simple.
SEE ALSO¶
OpenGL
AUTHORS & COPYRIGHTS¶
Made 2010 by Lars Stoltenow. OpenGL::XScreenSaver is free software; you may
redistribute it and/or modify it under the same terms as Perl itself.