1 """BulletML implementation."""
3 from __future__
import division
5 from math
import atan2
, sin
, cos
7 __all__
= ["Action", "Bullet"]
10 """Running action implementation.
12 To implement new actions, add a new element/class pair to
13 parser.ActionDef.CONSTRUCTORS. It should support FromXML,
14 __getstate__, and __setstate__, and 5-ary __call__:
16 def __call__(self, owner, action, params, rank, created)
18 Which will be called to execute it. This function should modify
19 owner, action, and created in-place, and return true if action
20 execution should stop for this bullet this frame.
24 def __init__(self
, parent
, actions
, params
, rank
, repeat
=1):
25 self
.actions
= actions
32 self
.direction_frames
= 0
37 self
.previous_fire_direction
= 0
38 self
.previous_fire_speed
= 0
43 self
.copy_state(parent
)
46 return "%s(pc=%r, actions=%r)" % (
47 type(self
).__name
__, self
.pc
, self
.actions
)
50 """End this action and its parents."""
56 def copy_state(self
, other
):
57 """Copy fire/movement state from other to self."""
58 self
.direction_frames
= other
.direction_frames
59 self
.direction
= other
.direction
60 self
.aiming
= other
.aiming
61 self
.speed_frames
= other
.speed_frames
62 self
.speed
= other
.speed
63 self
.accel_frames
= other
.accel_frames
66 self
.previous_fire_direction
= other
.previous_fire_direction
67 self
.previous_fire_speed
= other
.previous_fire_speed
69 def step(self
, owner
, created
):
70 """Advance by one frame."""
72 if self
.speed_frames
> 0:
73 self
.speed_frames
-= 1
74 owner
.speed
+= self
.speed
76 if self
.direction_frames
> 0:
77 self
.direction_frames
-= 1
78 # I'm still not sure what the aim check is supposed to do.
79 if self
.aiming
and self
.direction_frames
<= 0:
80 owner
.direction
+= owner
.aim
82 owner
.direction
+= self
.direction
84 if self
.accel_frames
> 0:
85 self
.accel_frames
-= 1
92 if self
.wait_frames
> 0:
96 s_params
= self
.params
103 action
= self
.actions
[self
.pc
]
109 if self
.parent
is not None:
110 self
.parent
.copy_state(self
)
111 owner
.replace(self
, self
.parent
)
115 action
= self
.actions
[self
.pc
]
117 if action(owner
, self
, s_params
, rank
, created
):
120 class Bullet(object):
121 """Simple bullet implementation.
124 x, y - current X/Y position
125 px, py - X/Y position prior to the last step
126 mx, my - X/Y axis-oriented speed modifier ("acceleration")
127 direction - direction of movement, in radians
128 speed - speed of movement, in units per frame
129 target - object with .x and .y fields for "aim" directions
130 vanished - set to true by a <vanish> action
131 rank - game difficulty, 0 to 1, default 0.5
132 tags - string tags set by the running actions
133 appearance - string used to set bullet appearance
135 Contructor Arguments:
136 x, y, direction, speed, target, rank, tags, appearance
137 - same as the above attributes
138 actions - internal action list
139 Action - custom Action constructor
143 def __init__(self
, x
=0, y
=0, direction
=0, speed
=0, target
=None,
144 actions
=(), rank
=0.5, tags
=(), appearance
=None):
149 self
.direction
= direction
151 self
.vanished
= False
154 self
.tags
= set(tags
)
155 self
.appearance
= appearance
156 self
.actions
= list(actions
)
159 def FromDocument(cls
, doc
, x
=0, y
=0, direction
=0, speed
=0, target
=None,
160 params
=(), rank
=0.5, Action
=Action
):
161 """Construct a new Bullet from a loaded BulletML document."""
162 actions
= [action(None, Action
, params
, rank
)
163 for action
in doc
.actions
]
164 return cls(x
=x
, y
=y
, direction
=direction
, speed
=speed
,
165 target
=target
, actions
=actions
, rank
=rank
)
168 return ("%s(%r, %r, accel=%r, direction=%r, speed=%r, "
169 "actions=%r, target=%r, appearance=vanished=%r)") % (
170 type(self
).__name
__, self
.x
, self
.y
, (self
.mx
, self
.my
),
171 self
.direction
, self
.speed
, self
.actions
, self
.target
,
172 self
.appearance
, self
.vanished
)
176 """Angle to the target, in radians.
178 If the target does not exist or cannot be found, return 0.
181 target_x
= self
.target
.x
182 target_y
= self
.target
.y
183 except AttributeError:
186 return atan2(target_x
- self
.x
, target_y
- self
.y
)
190 """Check if this bullet is finished running.
192 A bullet is finished when it has vanished, and all its
193 actions have finished.
195 If this is true, the bullet should be removed from the screen.
196 (You will probably want to cull it under other circumstances
199 if not self
.vanished
:
201 for action
in self
.actions
:
202 if not action
.finished
:
207 """Vanish this bullet and stop all actions."""
209 for action
in self
.actions
:
213 def replace(self
, old
, new
):
214 """Replace an active action with another.
216 This is mostly used by actions internally to queue children.
219 idx
= self
.actions
.index(old
)
223 self
.actions
[idx
] = new
226 """Advance by one frame.
228 This updates the position and velocity, and may also set the
231 It returns any new bullets this bullet spawned during this step.
235 for action
in self
.actions
:
236 action
.step(self
, created
)
239 direction
= self
.direction
242 self
.x
+= self
.mx
+ sin(direction
) * speed
243 self
.y
+= -self
.my
+ cos(direction
) * speed