+
+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)
+