Save and restore state of the game

Ability to 'save' (when the user closes the Activity) and 'restore' (when the
user launch it from the Journal or the Home without holding Alt) the state of
the game.

For this ability I had to upgrade 'olpcgames' to 1.6 because
'olpcgames.FILE_READ_REQUEST' and 'olpcgames.FILE_WRITE_REQUEST' events are
added in that version and those events are needed for this.

The data is saved (as JSON, with json module) in the 'event.metadata["state"]' and the timestamp state is saved in 'event.filename'.

This commit solves ticket #2393:
 * http://bugs.sugarlabs.org/ticket/2393

Signed-off-by: Manuel Kaufmann <humitos@gmail.com>
Signed-off-by: Rafael Ortiz <rafael@activitycentral.com>

1 files changed, 44 insertions, 5 deletions

diff --git a/game.py b/game.py
index 579c5c4..8482123 100644
--- a/game.py
+++ b/game.py
@@ -23,8 +23,15 @@
 
 import sys
 import time
-
+try:
+    import json
+except ImportError:
+    import simplejson as json
 import pygame
+import olpcgames
+
+import logging
+log = logging.getLogger('Maze')
 
 import olpcgames.pausescreen as pausescreen
 import olpcgames.mesh as mesh
@@ -94,8 +101,14 @@ class MazeGame:
 
         # start with a small maze using a seed that will be different
         # each time you play
-        self.maze = Maze(int(time.time()), int(9 * self.aspectRatio), 9)
+        data = {'seed': int(time.time()),
+                'width': int(9 * self.aspectRatio),
+                'height': 9}
+
+        log.debug('Starting the game with: %s', data)
+        self.maze = Maze(**data)
         self.reset()
+
         self.frame = 0
 
         self.font = pygame.font.Font(None, 30)
@@ -283,8 +296,33 @@ class MazeGame:
                     (event, sys.exc_info())
             else:
                 print "Message from unknown buddy?"
+
+        elif event.type == pygame.USEREVENT:
+            # process file save / restore events
+            if event.code == olpcgames.FILE_READ_REQUEST:
+                log.debug('Loading the state of the game...')
+                state = json.loads(event.metadata['state'])
+                log.debug('Loaded data: %s', state)
+                self.maze = Maze(**state)
+                self.reset()
+                return True
+            elif event.code == olpcgames.FILE_WRITE_REQUEST:
+                log.debug('Saving the state of the game...')
+                data = {'seed': self.maze.seed,
+                        'width': self.maze.width,
+                        'height': self.maze.height,
+                    }
+                log.debug('Saving data: %s', data)
+                event.metadata['state'] = json.dumps(data)
+                f = open(event.filename, 'w')
+                try:
+                    f.write(str(time.time()))
+                finally:
+                    f.close()
+                log.debug('Done saving.')
+                return True
         else:
-            print "Unknown event:", event
+            log.debug('Unknown event: %r', event)
 
     def handleMessage(self, player, message):
         """Handle a message from a player on the mesh.
@@ -357,11 +395,12 @@ class MazeGame:
     def run(self):
         """Run the main loop of the game."""
         # lets draw once before we enter the event loop
-        self.draw()
-        pygame.display.flip()
+
         clock = pygame.time.Clock()
+        pygame.display.flip()
 
         while self.running:
+            clock.tick(25)
             a, b, c, d = pygame.cursors.load_xbm('my_cursor.xbm',
                                                  'my_cursor_mask.xbm')
             pygame.mouse.set_cursor(a, b, c, d)