class Engine:
- """ A holder for game state. """
+ """ A holder for game state & scene management.
+ """
- def __init__(self, app, scene):
+ def __init__(self, app, scene, world):
self._app = app
self._scene = scene
+ self._world = world
+ self._viewport = (0, 0)
def _apply_events(self, events):
if not events:
ev.apply(self)
def change_scene(self, scene):
- self._scene.exit()
+ self._apply_events(self._scene.exit(self._world))
self._scene = scene
- self._scene.enter()
+ self._apply_events(self._scene.enter(self._world))
+
+ def change_world(self, *args, **kw):
+ self._world.apply_event(*args, **kw)
def quit_game(self):
from pgzero.game import exit
exit()
+ def move_screen(self, offset):
+ self._viewport = (self._viewport[0] + offset[0],
+ self._viewport[1] + offset[1])
+
@apply_events
def update(self, dt):
- return self._scene.update(dt)
+ return self._scene.update(self._world, dt)
def draw(self):
- self._scene.draw(self._app.screen)
+ self._scene.draw(self._app.screen, self._viewport)
@apply_events
def on_mouse_down(self, pos, button):
ENGINE_METHOD = "change_scene"
+class WorldEvent(Event):
+ """ Be a hero. Change the world. """
+
+ ENGINE_METHOD = "change_world"
+
+
class QuitEvent(Event):
""" Quit the game. """
ENGINE_METHOD = "quit_game"
+class MoveViewportEvent(Event):
+ """ Change to a new scene. """
+
+ ENGINE_METHOD = "move_screen"
+
+
class Actors:
""" A list of actors. """
def __init__(self):
self.actors = Actors()
- def enter(self):
+ def enter(self, world):
pass
- def exit(self):
+ def exit(self, world):
pass
- def update(self, dt):
+ def update(self, world, dt):
pass
- def draw(self, screen):
+ def draw(self, screen, viewport):
screen.clear()
self.actors.draw(screen)