Separate element constructors from regular constructors.

[python-bulletml.git] / bulletml / impl.py

diff --git a/bulletml/impl.py b/bulletml/impl.py
index 2c938d2..92982db 100644 (file)
--- a/bulletml/impl.py
+++ b/bulletml/impl.py
@@ -7,7 +7,7 @@ from __future__ import division
 
 import math
 
-from bulletml import parser, errors
+from bulletml import parser
 
 # TODO(jfw): This is very non-Pythonic, it's pretty much just the
 # BulletML reference ActionImpl translated to Python.
@@ -238,9 +238,9 @@ class Bullet(object):
         self.actions = []
         if rank is None:
             rank = parent.rank if parent else 0.5
-        for action, params in actions:
-            # New bullets reset the parent hierarchy.
-            self.actions.append(Action(self, None, action, params, rank))
+        # New bullets reset the parent hierarchy.
+        self.actions = [Action(self, None, action, params, rank)
+                        for action, params in actions]
 
     def __repr__(self):
         return ("%s(%r, %r, accel=%r, direction=%r, speed=%r, "
@@ -256,7 +256,7 @@ class Bullet(object):
             return self.direction
         else:
             return math.degrees(
-                math.atan2(self.target.x - self.x, self.target.y - self.y))
+                math.atan2(self.target.x - self.x, self.y - self.target.y))
 
     @property
     def finished(self):
@@ -287,6 +287,8 @@ class Bullet(object):
             created.extend(action.step())
 
         direction = math.radians(self.direction)
+        self.px = self.x
+        self.py = self.y
         self.x += self.mx + math.sin(direction) * self.speed
         self.y += self.my - math.cos(direction) * self.speed
 
@@ -295,6 +297,7 @@ class Bullet(object):
     @classmethod
     def FromDoc(cls, doc, params=(), x=0, y=0, speed=0, direction=0,
                 target=None, rank=0.5):
+        """Construct a bullet from top-level actions in a document."""
         actions = [act(params, rank) for act in doc.top]
         return cls(x, y, direction, speed, target, actions, rank=rank)