OpenGL::XScreenSaver(3pm)				User Contributed Perl Documentation				 OpenGL::XScreenSaver(3pm)

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.

perl v5.14.2							    2010-02-20						 OpenGL::XScreenSaver(3pm)