使用pygame写一个简单绕椭圆的点

import pygame
import sys
import numpy as np

class Solar():
    def __init__(self):
        pygame.init()

        self.WINDOW_WIDTH = 800
        self.WINDOW_HEIGHT = 400

        self.RED = (255, 0, 0)
        self.WHITE = (255, 255, 255)
        self.BLACK = (0, 0, 0)
        self.BLUE = (0,0,255)
        self.GREEN = (0,255,0)

        self.windows = pygame.display.set_mode((self.WINDOW_WIDTH, self.WINDOW_HEIGHT))
        pygame.display.set_caption('Solar simulation')

        self.init_figure()

        #初始化函数
    def init_figure(self):
        self.circle = pygame.image.load('circle_12_red.bmp')

        self.circle_rect = self.circle.get_rect()
        self.circle_rect.centerx = self.windows.get_rect().centerx
        self.circle_rect.centery = self.windows.get_rect().centery

        self.a = 300
        self.b = 150

        #椭圆路径
    def ellipse_path(self,x,flag):
        self.circle_rect.centerx = 400 + x
        self.circle_rect.centery = 200 - flag*((1-(x/self.a)**2)*(self.b**2))**0.5

        #循环内容
    def function(self,x,flag):
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                sys.exit()

        self.windows.fill(self.BLACK)
        pygame.draw.ellipse(self.windows, self.GREEN, (100, 50, 600, 300), 3)

        self.windows.blit(self.circle, self.circle_rect)

        pygame.display.flip()

        self.ellipse_path(x,flag)

        pygame.time.delay(5)

        #主控制
    def start_simulate(self):
        while True:
            #0-180度
            for x in np.arange(300,-300,-2):
                self.function(x,1)
            #180-360度
            for x in np.arange(-300,300,2):
                self.function(x,-1)

Solar().start_simulate()

写出来就是这个样子