bullet.py

import pygame
from pygame.sprite import Sprite

class Bullet(Sprite):
    '''A class to mange bullet fired from ship'''

    def __init__(self, ai_game):
        #create a bullet object at the ship's current position

        super().__init__()
        self.screen = ai_game.screen
        self.settings = ai_game.settings
        self.color = self.settings.bullet_color

        #create a bullet rect at (0,0) and set correct position
        self.rect = pygame.Rect(0,0, self.settings.bullet_width, self.settings.bullet_height)
        self.rect.midtop = ai_game.ship.rect.midtop

        #store bullet's position as decimal value
        self.y = float(self.rect.y)

    def update(self):
        #move the bullet up the screen
        
        self.y -= self.settings.bullet_speed # update the decimal position of the bullet
        self.rect.y = self.y # update the rect position

    def draw_bullet(self):
        #draw bullet to the screen
        pygame.draw.rect(self.screen, self.color, self.rect)