You have to create a list of bullets:
bullet_list = []
Add a new bullet position to the list when SPACE is pressed:
elif event.key == pygame.K_SPACE:
bullet_list.append([x + 15, y - 20])
Move and draw the bullets in the list in a loop:
for bullet in bullet_list:
pygame.draw.rect(screen, (250, 250, 0),
[*bullet, height_rect, width_rect])
bullet[1] -= 5
Delete a bullet from the list if the y-coordinate is less than 0:
for bullet in bullet_list[:]:
if bullet[1] < 0:
bullet_list.remove(bullet)
Complete example:
import pygame
pygame.init()
screen_size = (500, 500)
ship_size = (50, 50)
x, y = 250, 450
x_rect, y_rect = x + 15, y - 20
height_rect, width_rect = 20, 20
vel = 50
bullet_list = []
"""Loads screen and set gives it a title."""
screen = pygame.display.set_mode(screen_size)
pygame.display.set_caption("Space Invaders")
"""Initializes images for the game and resizes them."""
space_ship = pygame.image.load("Space Invaders Ship.jpg")
space_ship = pygame.transform.scale(space_ship, ship_size)
space = pygame.image.load("Space.jpg")
space = pygame.transform.scale(space, screen_size)
clock = pygame.time.Clock()
run = True
while run:
"""Controls the fps."""
clock.tick(60)
"""Registers keyboard's input."""
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_LEFT and x > 0:
x -= vel
elif event.key == pygame.K_RIGHT and x + 50 < 500:
x += vel
elif event.key == pygame.K_SPACE:
bullet_list.append([x + 15, y - 20])
"""Constantly draws on the screen."""
screen.fill((0, 0, 0))
screen.blit(space, (0, 0))
screen.blit(space_ship, [x, y])
"""Shoots a bullet from where the ship currently is."""
for bullet in bullet_list:
pygame.draw.rect(screen, (250, 250, 0),
[*bullet, height_rect, width_rect])
bullet[1] -= 5
for bullet in bullet_list[:]:
if bullet[1] < 0:
bullet_list.remove(bullet)
pygame.display.flip()