X-Git-Url: https://git.ctpug.org.za/?a=blobdiff_plain;f=koperkapel%2Fscenes%2Fbase.py;h=ade4d8bfddede638919ab9eb884423d38a9e55c6;hb=0e3ff44e339e83cc26196e9fcd20193dbd65a46c;hp=58f3874f204b87a874751d593f4360a785791a70;hpb=9ac7ed8018955d9a80545c2f523964408d9668d9;p=koperkapel.git

diff --git a/koperkapel/scenes/base.py b/koperkapel/scenes/base.py
index 58f3874..ade4d8b 100644
--- a/koperkapel/scenes/base.py
+++ b/koperkapel/scenes/base.py
@@ -13,11 +13,14 @@ def apply_events(f):
 
 
 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:
@@ -26,20 +29,31 @@ class Engine:
             ev.apply(self)
 
     def change_scene(self, scene):
-        self._scene.exit()
+        self._apply_events(self._scene.exit(self._world.proxy()))
         self._scene = scene
-        self._scene.enter()
+        self._apply_events(self._scene.enter(self._world.proxy()))
+
+    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])
+
+    def calc_offset(self, x, y):
+        """Return a position offset by the viewport"""
+        return x - self._viewport[0], y - self._viewport[1]
+
     @apply_events
     def update(self, dt):
-        return self._scene.update(dt)
+        return self._scene.update(self._world.proxy(), self, 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):
@@ -81,29 +95,83 @@ class ChangeSceneEvent(Event):
     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 Actors:
-    """ A list of actors. """
+class MoveViewportEvent(Event):
+    """ Change to a new scene. """
 
-    def __init__(self):
-        self._actors = []
+    ENGINE_METHOD = "move_screen"
+
+
+class Layer:
+    """ A single layer of actors. """
+
+    def __init__(self, name):
+        self.name = name
+        self.actors = []
+
+    def __iter__(self):
+        return iter(self.actors)
+
+    def __getitem__(self, i):
+        return self.actors[i]
+
+    def __len__(self):
+        return len(self.actors)
 
     def add(self, actor):
-        self._actors.append(actor)
+        self.actors.append(actor)
         return actor
 
+    def clear(self):
+        self.actors.clear()
+
     def remove(self, actor):
-        self._actors.remove(actor)
+        self.actors.remove(actor)
         return actor
 
+
+class Actors:
+    """ Layers of actors.
+
+    Actors may be rendered in different layers. Layers with lower levels
+    are rendered lower than layers with higher ones.
+    """
+
+    def __init__(self):
+        self._ordered_layers = []
+        self._layers = {}
+        self.add_layer("default", 0)
+
+    def __getattr__(self, name):
+        return self._layers[name]
+
+    def add_layer(self, name, level):
+        layer = self._layers[name] = Layer(name)
+        self._ordered_layers.append((level, name))
+        self._ordered_layers.sort()
+        return layer
+
+    def add(self, actor, layer="default"):
+        return self._layers[layer].add(actor)
+
+    def remove(self, actor, layer="default"):
+        return self._layers[layer].remove(actor)
+
     def draw(self, screen):
-        for actor in self._actors:
-            actor.draw()  # TODO: allow an option screen to be passed in
+        for lvl, name in self._ordered_layers:
+            for actor in self._layers[name]:
+                actor.draw()  # TODO: allow an option screen to be passed in
 
 
 class Scene:
@@ -112,16 +180,16 @@ class Scene:
     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, engine, dt):
         pass
 
-    def draw(self, screen):
+    def draw(self, screen, viewport):
         screen.clear()
         self.actors.draw(screen)