问题
i am trying to get my explosion image to disappear after a bullet collision with an alien. i am able to get the explosion to appear when the collision happens but can't seem to get it to disappear afterwards. i would like the explosion image to disappear after maybe 1 second or so. i understand that it would possibly involve a game clock and a kill method? thank you.
import sys
import pygame
from settings import Settings
from ship import Ship
from bullet import Bullet
from alien import Alien
from pygame.sprite import Sprite
class AlienInvasion:
"""overall class to manage game assets and behavior"""
def __init__(self):
"""initialize that game and create game resources"""
pygame.init()
self.settings = Settings()
self.screen = pygame.display.set_mode(
(self.settings.screen_width, self.settings.screen_height))
pygame.display.set_caption("Alien Invasion")
self.ship = Ship(self)
self.bullets = pygame.sprite.Group()
self.aliens = pygame.sprite.Group()
self.all_sprites = pygame.sprite.Group()
self._create_fleet()
# set the background color
# set the background color
def run_game(self):
"""start the main loop for the game"""
while True:
self._check_events()
self.ship.update()
self._update_bullets()
self._update_aliens()
self._update_screen()
def _check_events(self):
"""respond to keypress and mouse events"""
for event in pygame.event.get():
if event.type == pygame.QUIT:
sys.exit()
elif event.type == pygame.KEYDOWN:
self._check_keydown_events(event)
elif event.type == pygame.KEYUP:
self._check_keyup_events(event)
def _check_keydown_events(self, event):
"""respons to key presses"""
if event.key == pygame.K_RIGHT:
self.ship.moving_right = True
elif event.key == pygame.K_LEFT:
self.ship.moving_left = True
elif event.key == pygame.K_SPACE:
self._fire_bullet()
elif event.key == pygame.K_q:
sys.exit()
def _check_keyup_events(self, event):
""" respond to key releases """
if event.key == pygame.K_RIGHT:
self.ship.moving_right = False
elif event.key == pygame.K_LEFT:
self.ship.moving_left = False
def _fire_bullet(self):
"""create a new bullet and add it to the bullet group"""
if len(self.bullets) < self.settings.bullets_allowed:
new_bullet = Bullet(self)
self.bullets.add(new_bullet)
def _update_bullets(self):
"""update positions of the bullets and get rid of old bullets"""
# update bullet position
self.bullets.update()
# get rid of bullets that have disappeared
for bullet in self.bullets.copy():
if bullet.rect.bottom <= 0:
self.bullets.remove(bullet)
collisions = pygame.sprite.groupcollide(self.bullets, self.aliens,
True, True)
for collision in collisions:
expl = Explosion(collision.rect.center)
self.all_sprites.add(expl)
def _update_aliens(self):
"""update the positions of all the aliens in the fleet"""
self._check_fleet_edges()
self.aliens.update()
def _create_fleet(self):
alien = Alien(self)
alien_place = alien.rect.x
alien_other_place = alien.rect.y
for row_number in range(4):
for alien_number in range(9):
alien = Alien(self)
alien.rect.x = alien_place + 110 * alien_number
alien.rect.y = alien_other_place + 120 * row_number
self.aliens.add(alien)
def _check_fleet_edges(self):
for alien in self.aliens:
if alien.check_edges():
self._change_fleet_direction()
break
def _change_fleet_direction(self):
for alien in self.aliens:
alien.rect.y += self.settings.fleet_drop_speed
self.settings.fleet_direction *= -1
def _update_screen(self):
"""update images on the screen and flip to the new screen"""
self.screen.fill(self.settings.bg_color)
self.ship.blitme()
for bullet in self.bullets:
bullet.draw_bullet()
self.aliens.draw(self.screen)
self.all_sprites.draw(self.screen)
pygame.display.flip()
class Explosion(Sprite):
def __init__(self, center):
super().__init__()
self.image = pygame.image.load('images/explo.bmp')
self.rect = self.image.get_rect()
self.rect.center = center
if __name__ == '__main__':
# make a game instance, and run the game
ai = AlienInvasion()
ai.run_game()
回答1:
You have to add another group for the explosions and to add the new Explosion object to this group, too:
class AlienInvasion:
# [...]
def __init__(self):
# [...]
self.explosions = pygame.sprite.Group()
# [...]
def _update_bullets(self):
# [...]
for collision in collisions:
expl = Explosion(collision.rect.center)
self.explosions.add(expl)
self.all_sprites.add(expl)
Get the current time (pygame.time.get_ticks()) when the Explosion object is constructed and kill() the object in the update method after a certain time span:
class Explosion(Sprite):
def __init__(self, center):
super().__init__()
self.image = pygame.image.load('images/explo.bmp')
self.rect = self.image.get_rect()
self.rect.center = center
self.start_time = pygame.time.get_ticks()
def update(self):
current_time = pygame.time.get_ticks()
timespan = 1000 # 1000 milliseconds = 1 second
if current_time > self.start_time + timespan:
self.kill()
Do not forget to invoke self.explosions.update() in AlienInvasion._update_bullets:
class AlienInvasion:
# [...]
def _update_bullets(self):
# [...]
self.explosions.update()
来源：https://stackoverflow.com/questions/62614228/trying-to-get-sprite-to-disappear-from-screen-after-certain-amount-of-time