def __init__(self, speed=0., course=0., acceleration=0., max_speed=0., rotation_speed=0.):
"""Constructor.
speed {float} Initial speed.
course {float} Initial course.
acceleration {float} Max velocity change per second.
max_speed {float} Maximum speed per second.
rotation_speed {float} Max degrees rotation change per second.
"""
# Set defaults so our caching of properties works.
self.speed = speed
self.course = Heading(course)
self.acceleration = acceleration
self.max_speed = max_speed
self.rotation_speed = rotation_speed
# {float|None}
self.target_speed = None
# {Heading|None}
self.target_course = None
class Velocity(Component):
"""Provides motion for entity, along with some basic velocity helpers.
"""
_cname = "velocity"
def __init__(self, speed=0., course=0., acceleration=0., max_speed=0., rotation_speed=0.):
"""Constructor.
speed {float} Initial speed.
course {float} Initial course.
acceleration {float} Max velocity change per second.
max_speed {float} Maximum speed per second.
rotation_speed {float} Max degrees rotation change per second.
"""
# Set defaults so our caching of properties works.
self.speed = speed
self.course = Heading(course)
self.acceleration = acceleration
self.max_speed = max_speed
self.rotation_speed = rotation_speed
# {float|None}
self.target_speed = None
# {Heading|None}
self.target_course = None
@property
def speed(self):
""" {float} Magnitude of our course.
"""
return self._speed
@speed.setter
def speed(self, value):
self._speed = abs(float(value))
@property
def course(self):
""" {float} course in degrees.
"""
return self._course
@course.setter
def course(self, value):
""" {number} set in degrees.
"""
self._course = Heading(value)
@property
def acceleration(self):
return self._acceleration
@acceleration.setter
def acceleration(self, value):
self._acceleration = float(value)
@property
def max_speed(self):
return self._max_speed
@max_speed.setter
def max_speed(self, value):
self._max_speed = float(value)
@property
def rotation_speed(self):
return self._rotation_speed
@rotation_speed.setter
def rotation_speed(self, value):
self._rotation_speed = float(value)
@property
def target_speed(self):
return self._target_speed
@target_speed.setter
def target_speed(self, value):
self._target_speed = mmval(self.max_speed, float(value)) if value is not None else None
@property
def target_course(self):
return self._target_course
@target_course.setter
def target_course(self, value):
if value is not None:
self._target_course = Heading(value)
else:
self._target_course = None
@property
def deltaxy(self):
"""{tuple} A screen coordinate friendly (upper left is left, positive
x is right, positive y is down) velocity vector in one unit time.
"""
deltas = self._course.screenxy
return (deltas[0]*self.speed, deltas[1]*self.speed)
def fullspeedto(self, locimp_or_course):
"""Aims target velocity toward an entity or along a course.
locimp_or_course {mixed} Either an object that implements the location
interface defined in this game, or a generic heading object representing
course (numbers are okay, they are converted to Headings).
"""
self.target_speed = self.max_speed
if (hasattr(locimp_or_course, "location")):
self.target_course = courseto(self.entity.location, locimp_or_course.location)
else:
self.target_course = locimp_or_course
def stop(self):
"""Keep same course, bring speed to 0.
"""
self.target_speed = 0.
self.target_course = None
def process(self, time_passed):
"""Manage velocity.
"""
if self.target_speed != None and self.target_speed != self.speed:
direction = 1 if self.target_speed > self.speed else -1
delta = time_passed * self.acceleration
speed = self.speed + math.copysign(delta, direction)
self.speed = mmval(self.target_speed, speed)
if self.target_course != None and self.target_course != self.course:
angleto = self.course.angleto(self.target_course)
direction = -1 if angleto <= 0 else 1
delta = direction * time_passed * self.rotation_speed
if abs(delta) <= abs(angleto):
self.course += delta
else:
self.course = self.target_course
loc = self.entity.location
dx, dy = self.deltaxy
self.entity.location = loc[0]+dx*time_passed, loc[1]+dy*time_passed