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meunomemauricio/fixed_pendulum.py

Last active October 27, 2022 15:30
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Simple Pendulum simulation using Pyglet + PyMunk
Raw
fixed_pendulum.py
"""Fixed Pendulum Simulation using PyMunk and Pyglet."""
import pymunk
import pyglet
from pyglet.window import key
from pymunk import Vec2d
from pymunk.pyglet_util import DrawOptions
class Pendulum:
"""Fixed Pendulum PyMunk Model."""
MASS = 0.100 # kg
FORCE = 10 # mN
def __init__(self, space: pymunk.Space):
self.space = space
self._create_entities()
def _create_entities(self) -> None:
"""Create the entities that form the Pendulum."""
self.static_body = pymunk.Body(body_type=pymunk.Body.STATIC)
self.static_body.position = (360, 360)
moment = pymunk.moment_for_circle(
mass=self.MASS, inner_radius=0, outer_radius=10.0
)
self.circle_body = pymunk.Body(mass=self.MASS, moment=moment)
self.circle_body.position = (360, 50)
circle_shape = pymunk.Circle(body=self.circle_body, radius=10.0)
rod_joint = pymunk.constraints.PinJoint(
a=self.static_body,
b=self.circle_body,
)
self.space.add(
self.static_body, self.circle_body, circle_shape, rod_joint
)
@property
def angle(self) -> float:
"""Angle (deg) between the Pendulum and the resting location."""
return Vec2d(0, -1).get_angle_degrees_between(self.vector)
@property
def vector(self) -> Vec2d:
"""Pendulum Vector, from Fixed point to the center of the Circle."""
return self.circle_body.position - self.static_body.position
def accelerate(self, direction: Vec2d):
"""Apply force in the direction `dir`."""
impulse = self.FORCE * direction.normalized()
self.circle_body.apply_impulse_at_local_point(impulse=impulse)
class SimulationWindow(pyglet.window.Window):
"""Application simulating the Fixed Pendulum."""
CAPTION = "PyMunk Fixed Pendulum Simulation."
WIDTH = 720
HEIGHT = 720
INTERVAL = 1.0 / 100 # 100 updates / second
FONT_SIZE = 16
FONT_COLOR = (255, 255, 255, 255)
def __init__(self):
super().__init__(
width=self.WIDTH, height=self.HEIGHT, caption=self.CAPTION
)
self.space = pymunk.Space()
self.space.gravity = Vec2d(0, -9807) # mm/s²
self.model = Pendulum(space=self.space)
self.draw_options = DrawOptions()
self.keyboard = key.KeyStateHandler()
self.push_handlers(self.keyboard)
self.angle_label = pyglet.text.Label(
font_size=self.FONT_SIZE,
x=5,
y=self.height - self.FONT_SIZE - 1,
color=self.FONT_COLOR,
bold=True,
)
pyglet.clock.schedule_interval(self.update, interval=self.INTERVAL)
def _handle_input(self):
"""Handle application input."""
if self.keyboard[key.LEFT]:
direction = self.model.vector.rotated_degrees(-90) # CW
self.model.accelerate(direction=direction)
elif self.keyboard[key.RIGHT]:
direction = self.model.vector.rotated_degrees(90) # CCW
self.model.accelerate(direction=direction)
def on_draw(self) -> None:
"""Screen Draw Event."""
self.clear()
self.space.debug_draw(options=self.draw_options)
self.angle_label.draw()
def update(self, dt: float) -> None:
"""Update PyMunk's Space state.
:param float dt: Time between calls of `update`.
"""
self._handle_input()
self.space.step(dt=self.INTERVAL)
self.angle_label.text = f"Angle: {self.model.angle:4.0f}°"
# Run application, if executing the module.
if __name__ == "__main__":
SimulationWindow()
pyglet.app.run()
Raw
requirements.txt
pyglet==1.5.27
pymunk==6.2.1
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