X-Git-Url: https://git.yukkurigames.com/?p=python-bulletml.git;a=blobdiff_plain;f=bulletml%2Fimpl.py;h=3326ceccc7a230a6d1d07d93bd7cae10c4e0ad3f;hp=92982db02afd4d128f8b475b7f42937b0baabd42;hb=41f351faf847cb5bc88c7ff5fc6c21bafc9aa5ee;hpb=ef50d69288ee60ac2a8fae2ffe5860e80299fd72

diff --git a/bulletml/impl.py b/bulletml/impl.py
index 92982db..3326cec 100644
--- a/bulletml/impl.py
+++ b/bulletml/impl.py
@@ -12,22 +12,23 @@ from bulletml import parser
 # TODO(jfw): This is very non-Pythonic, it's pretty much just the
 # BulletML reference ActionImpl translated to Python.
 
+PI_2 = math.pi * 2
+
+__all__ = ["Action", "Bullet"]
+
 class Action(object):
     """Running action implementation."""
 
-    def __init__(self, owner, parent, actions, params, rank):
+    def __init__(self, owner, parent, actions, params, rank, repeat=1):
         self.actions = actions
         self.parent = parent
-        self.repeat = 1
+        self.repeat = repeat
         self.wait_frames = 0
         self.speed = 0
         self.speed_frames = 0
-        self.aim_direction = 0
         self.direction = 0
         self.direction_frames = 0
         self.aiming = False
-        self.aim_mx = 0
-        self.aim_my = 0
         self.mx = 0
         self.my = 0
         self.owner = owner
@@ -37,6 +38,7 @@ class Action(object):
         self.params = params
         self.rank = rank
         self.pc = -1
+        self.finished = False
         if parent:
             self.copy_state(parent)
 
@@ -44,16 +46,15 @@ class Action(object):
         return "%s(pc=%r, actions=%r)" % (
             type(self).__name__, self.pc, self.actions)
 
-    @property
-    def finished(self):
-        return self.pc is None
-
     def vanish(self):
+        """End this action and its parents."""
         if self.parent:
             self.parent.vanish()
         self.pc = None
+        self.finished = True
 
     def copy_state(self, other):
+        """Copy fire/movement state from other to self."""
         self.direction_frames = other.direction_frames
         self.direction = other.direction
         self.aiming = other.aiming
@@ -66,6 +67,7 @@ class Action(object):
         self.previous_fire_speed = other.previous_fire_speed
 
     def step(self):
+        """Advance by one frame."""
         created = []
 
         if self.speed_frames > 0:
@@ -73,10 +75,13 @@ class Action(object):
             self.owner.speed += self.speed
 
         if self.direction_frames > 0:
+            # The Noiz implementation was a little weird here, I think
+            # there was a bug in it that prevented it from working if
+            # the frame count was 1. I'm still not sure what the aim
+            # check is supposed to do, exactly.
             self.direction_frames -= 1
-            if self.direction_frames <= 0:
-                if self.aiming:
-                    self.owner.direction += self.owner.aim
+            if self.aiming and self.direction_frames <= 0:
+                self.owner.direction += self.owner.aim
             else:
                 self.owner.direction += self.direction
 
@@ -95,23 +100,25 @@ class Action(object):
         while True:
             self.pc += 1
 
-            if self.pc >= len(self.actions):
+            try:
+                action = self.actions[self.pc]
+            except IndexError:
                 self.repeat -= 1
                 if self.repeat <= 0:
                     self.pc = None
+                    self.finished = True
                     if self.parent is not None:
                         self.parent.copy_state(self)
                         self.owner.replace(self, self.parent)
                     break
                 else:
                     self.pc = 0
-
-            action = self.actions[self.pc]
+                    action = self.actions[self.pc]
 
             if isinstance(action, parser.Repeat):
                 repeat, (actions, params) = action(self.params, self.rank)
-                child = Action(self.owner, self, actions, params, self.rank)
-                child.repeat = repeat
+                child = Action(
+                    self.owner, self, actions, params, self.rank, repeat)
                 self.owner.replace(self, child)
                 created.extend(child.step())
                 break
@@ -137,14 +144,16 @@ class Action(object):
                     direction = self.owner.aim
                 self.previous_fire_direction = direction
 
-
                 if speed:
                     speed, type = speed
                     if type == "sequence":
                         speed += self.previous_fire_speed
                     elif type == "relative":
-                        # FIXME(jfw): Reference impl uses prvFireSpeed
-                        # here?  That doesn't seem right at all.
+                        # The reference Noiz implementation uses
+                        # prvFireSpeed here, but the standard is
+                        # pretty clear -- "0 means that the direction
+                        # of this fire and the direction of the bullet
+                        # are the same".
                         speed += self.owner.speed
                 else:
                     speed = 1
@@ -169,27 +178,24 @@ class Action(object):
                 self.direction_frames = frames
                 self.aiming = False
                 if type == "sequence":
-                    self.aiming = False
                     self.direction = direction
                 else:
                     if type == "absolute":
-                        self.aiming = False
                         self.direction = (
-                            direction - self.owner.direction) % 360
+                            direction - self.owner.direction) % PI_2
                     elif type == "relative":
-                        self.aiming = False
                         self.direction = direction
                     else:
                         self.aiming = True
                         self.direction = (
                             direction
                             + self.owner.aim
-                            - self.owner.direction) % 360
+                            - self.owner.direction) % PI_2
 
-                    while self.direction > 180:
-                        self.direction -= 360
-                    while self.direction < -180:
-                        self.direction += 360
+                    if self.direction > math.pi:
+                        self.direction -= PI_2
+                    if self.direction < -math.pi:
+                        self.direction += PI_2
                     self.direction /= self.direction_frames
 
             elif isinstance(action, parser.Accel):
@@ -223,7 +229,24 @@ class Action(object):
         return created
 
 class Bullet(object):
-    """Simple bullet implementation."""
+    """Simple bullet implementation.
+
+    Attributes:
+    x, y - current X/Y position
+    px, py - X/Y position prior to the last step
+    mx, my - X/Y axis-oriented speed modifier ("acceleration")
+    direction - direction of movement, in radians
+    speed - speed of movement, in units per frame
+    target - object with .x and .y fields for "aim" directions
+    vanished - set to true by a <vanish> action
+
+    Contructor Arguments:
+    x, y, direction, speed, target - same as the attributes
+    actions - internal action list
+    parent - parent of actions, None for manually-created bullets
+    rank - game difficulty, 0 to 1
+
+    """
 
     def __init__(self, x=0, y=0, direction=0, speed=0, target=None,
                  actions=(), parent=None, rank=None):
@@ -235,69 +258,80 @@ class Bullet(object):
         self.speed = speed
         self.vanished = False
         self.target = target
-        self.actions = []
         if rank is None:
             rank = parent.rank if parent else 0.5
         # New bullets reset the parent hierarchy.
-        self.actions = [Action(self, None, action, params, rank)
-                        for action, params in actions]
+        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, "
                 "actions=%r, target=%r, vanished=%r)") % (
             type(self).__name__, self.x, self.y, (self.mx, self.my),
-            self.direction, self.speed, self.actions, self.target,
+            self.direction, self.speed, self._actions, self.target,
             self.vanished)
 
     @property
     def aim(self):
-        """Angle to the target."""
+        """Angle to the target, in radians."""
         if self.target is None:
             return self.direction
         else:
-            return math.degrees(
-                math.atan2(self.target.x - self.x, self.y - self.target.y))
+            return math.atan2(self.target.x - self.x, self.y - self.target.y)
 
     @property
     def finished(self):
-        for action in self.actions:
+        """Check if this bullet is finished running.
+
+        A bullet is finished when it has vanished, and all its
+        actions have finished.
+
+        If this is true, the bullet should be removed from the screen.
+        (You will probably want to cull it under other circumstances
+        as well).
+        """
+        if not self.vanished:
+            return False
+        for action in self._actions:
             if not action.finished:
                 return False
-        return self.vanished
+        return True
 
     def vanish(self):
         """Vanish this bullet and stop all actions."""
         self.vanished = True
-        for action in self.actions:
+        for action in self._actions:
             action.vanish()
-        self.actions = []
+        self._actions = []
 
     def replace(self, old, new):
+        """Replace an active action with another.
+
+        This is mostly used by actions internally to queue children.
+        """
         try:
-            idx = self.actions.index(old)
+            idx = self._actions.index(old)
         except ValueError:
             pass
         else:
-            self.actions[idx] = new
+            self._actions[idx] = new
 
     def step(self):
+        """Advance by one frame.
+
+        This updates the position and velocity, and may also set the
+        vanished flag.
+
+        It returns any new bullets this bullet spawned during this step.
+        """
         created = []
 
-        for action in self.actions:
+        for action in self._actions:
             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
+        self.x += self.mx + math.sin(self.direction) * self.speed
+        self.y += self.my - math.cos(self.direction) * self.speed
 
         return created
-
-    @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)
-