[OLPC-Games] Camera functionality in olpcgames

[Mike C. Fletcher]

The current Camera implementation in olpcgames has a number of issues, 
not least of which is that if your gstreamer bus fails for any reason, 
your "snap" call will never return (and in my tests, that hangs your 
entire GUI).  I've reimplemented the Camera class to provide a number of 
features, the most important of which is an asynchronous API that 
delivers the captured image as a Pygame event, rather than returning it 
directly from the "snap" call.  It also allows you to specify the image 
format and data source (e.g. to use a testing source on machines without 
v4l2src sources available).

The current API should still work, though I don't see a lot of 
activities that actually use the camera. "snap" should be considered 
deprecated at the moment, as it is not particularly safe (it could be 
made safe with some work, it just isn't now).  I've also refactored the 
code so that the same code can be used for initialising the gstreamer 
pipeline, loading the images etceteras for all of the entry points.

Changes should land as soon as I get write access to the repository.  At 
the moment the only code I see that uses it is the TicTacToe test stuff 
(doesn't seem very useful there, but I've converted it to the async api 
anyway).

Example of use:

                elif evt.key == pygame.K_a:
                    cam.snap_async( 'you', source='test' )
            elif evt.type in (olpcgames.camera.CAMERA_LOAD, 
olpcgames.camera.CAMERA_LOAD_FAIL):
                if evt.success
                    if evt.token == 'you':
                         pic = evt.image
                else:
                    print 'Failure loading picture: %s'%( evt.err, )

Have fun,
Mike

-- 
________________________________________________
  Mike C. Fletcher
  Designer, VR Plumber, Coder
  http://www.vrplumber.com
  http://blog.vrplumber.com