From bf20049741bc0d599092143738e4633f1f87de8f Mon Sep 17 00:00:00 2001
From: Simon Cross <hodgestar@gmail.com>
Date: Wed, 2 Mar 2016 22:23:49 +0200
Subject: [PATCH] Better layer management.

---
 koperkapel/scenes/base.py    | 40 ++++++++++++++++++++++++++----------
 koperkapel/scenes/roaches.py | 14 ++++++-------
 2 files changed, 36 insertions(+), 18 deletions(-)

diff --git a/koperkapel/scenes/base.py b/koperkapel/scenes/base.py
index d0b9a95..fd53f81 100644
--- a/koperkapel/scenes/base.py
+++ b/koperkapel/scenes/base.py
@@ -109,34 +109,52 @@ class MoveViewportEvent(Event):
     ENGINE_METHOD = "move_screen"
 
 
+class Layer:
+    """ A single layer of actors. """
+
+    def __init__(self, name):
+        self.name = name
+        self.actors = []
+
+    def add(self, actor):
+        self.actors.append(actor)
+        return actor
+
+    def remove(self, actor):
+        self.actors.remove(actor)
+        return actor
+
+
 class Actors:
-    """ A list of 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._layer_order = []
+        self._ordered_layers = []
         self._layers = {}
         self.add_layer("default", 0)
 
+    def __getattr__(self, name):
+        return self._layers[name]
+
     def add_layer(self, name, level):
-        self._layer_order.append((level, name))
-        self._layer_order.sort()
-        self._layers[name] = []
+        layer = self._layers[name] = Layer(name)
+        self._ordered_layers.append((level, name))
+        self._ordered_layers.sort()
+        return layer
 
     def add(self, actor, layer="default"):
-        self._layers[layer].append(actor)
-        return actor
+        return self._layers[layer].add(actor)
 
     def remove(self, actor, layer="default"):
-        self._layers[layer].remove(actor)
-        return actor
+        return self._layers[layer].remove(actor)
 
     def draw(self, screen):
-        for lvl, layer in self._layer_order:
-            for actor in self._layers[layer]:
+        for lvl, name in self._ordered_layers:
+            for actor in self._layers[name].actors:
                 actor.draw()  # TODO: allow an option screen to be passed in
 
 
diff --git a/koperkapel/scenes/roaches.py b/koperkapel/scenes/roaches.py
index 7198ee2..09169f3 100644
--- a/koperkapel/scenes/roaches.py
+++ b/koperkapel/scenes/roaches.py
@@ -12,17 +12,17 @@ class RoachesScene(Scene):
 
     def __init__(self):
         super().__init__()
-        self.actors.add_layer("pads", level=5)
-        self.actors.add_layer("roaches", level=10)
         self._roach_actors = {}
+        self._roaches = self.actors.add_layer("roaches", level=10)
+        self._pads = self.actors.add_layer("pads", level=5)
         self._init_pads()
 
     def _init_pads(self):
-        self._roach_pad = self.actors.add(
-            Actor("roach_management/roach_pad"), layer="pads")
+        self._roach_pad = self._pads.add(
+            Actor("roach_management/roach_pad"))
         self._roach_pad.pos = (WIDTH * (7/8), HEIGHT * (1/4))
-        self._inventory_pad = self.actors.add(
-            Actor("roach_management/inventory_pad"), layer="pads")
+        self._inventory_pad = self._pads.add(
+            Actor("roach_management/inventory_pad"))
         self._inventory_pad.pos = (WIDTH * (7/8), HEIGHT * (3/4))
 
     def update(self, world, dt):
@@ -36,7 +36,7 @@ class RoachesScene(Scene):
                         roach.attributes.items()),
                     )))
                 self._roach_actors[roach.name] = actor
-                self.actors.add(actor, layer="roaches")
+                self._roaches.add(actor)
             # TODO: remove missing roaches
             actor.pos = (300, 100 + i * 100)
 
-- 
2.34.1