محاكاة بسيطة للمساحة باستخدام Python و Box2D

المقدمة

from Box2D.examples.framework import Framework
from Box2D import *

class Simulation(Framework):
    def __init__(self):
        super(Simulation, self).__init__()

        # Ground body
        self.world.CreateBody(shapes=b2LoopShape(vertices=[(20, 0), (20, 40), (-20, 40), (-20, 0)]))
        # Dynamic body
        circle = b2FixtureDef(shape=b2CircleShape(radius=2), density=1, friction=1.0, restitution=0.5)
        self.world.CreateBody(type=b2_dynamicBody, position=b2Vec2(0,30), fixtures=circle, linearVelocity=(5, 0))

    def Step(self, settings):
        super(Simulation, self).Step(settings)

if __name__ == "__main__":
    Simulation().run()

أطلقنا القمر الصناعي

from Box2D import *
from Box2D.examples.framework import Framework


class Simulation(Framework):
    def __init__(self):
        super(Simulation, self).__init__()

        # Default gravity disable
        self.world.gravity = (0.0, 0.0)
        # Gravity constant
        self.G = 100

        # Planet
        circle = b2FixtureDef(shape=b2CircleShape(radius=5), density=1, friction=0.5, restitution=0.5)
        self.world.CreateBody(type=b2_dynamicBody, position=b2Vec2(0,0), fixtures=circle)

        # Satellite
        circle_small = b2FixtureDef(shape=b2CircleShape(radius=0.2), density=1, friction=0.5, restitution=0.2)
        self.world.CreateBody(type=b2_dynamicBody, position=b2Vec2(0, 10), fixtures=circle_small, linearVelocity=(20, 0))

    def Step(self, settings):
        super(Simulation, self).Step(settings)

        # Simulate the Newton's gravity
        for bi in self.world.bodies:
            for bk in self.world.bodies:
                if bi == bk:
                    continue

                pi, pk = bi.worldCenter, bk.worldCenter
                mi, mk = bi.mass, bk.mass
                delta = pk - pi
                r = delta.length
                if abs(r) < 1.0:
                    r = 1.0

                force = self.G * mi * mk / (r * r)
                delta.Normalize()
                bi.ApplyForce(force * delta, pi, True)

if __name__ == "__main__":
    Simulation().run()

circle_small = b2FixtureDef(shape=b2CircleShape(radius=0.2), density=1, friction=0.5, restitution=0.2)
circle_medium = b2FixtureDef(shape=b2CircleShape(radius=0.3), density=1, friction=1.0, restitution=0.5)
self.world.CreateBody(type=b2_dynamicBody, position=b2Vec2(0, 6), fixtures=circle_small, linearVelocity=(37, 0))
self.world.CreateBody(type=b2_dynamicBody, position=b2Vec2(0, 10), fixtures=circle_small, linearVelocity=(28, 0))
self.world.CreateBody(type=b2_dynamicBody, position=b2Vec2(0, 15), fixtures=circle_medium, linearVelocity=(22, 0))

استنتاج