让敌人随意射击#

让敌人随机射击比定期射击敌人更容易，如所示 让敌人定期射击 。这是因为我们不需要跟踪距离上次开火有多长时间。

有关此示例的特定内容，请参阅突出显示的行。

使用精灵拍摄物体的截图
sprite_bullets_random.py#
  1"""
  2Show how to have enemies shoot bullets at random intervals.
  3
  4If Python and Arcade are installed, this example can be run from the command line with:
  5python -m arcade.examples.sprite_bullets_random
  6"""
  7import arcade
  8import random
  9
 10SCREEN_WIDTH = 800
 11SCREEN_HEIGHT = 600
 12SCREEN_TITLE = "Sprites and Random Bullets Example"
 13
 14
 15class MyGame(arcade.Window):
 16    """ Main application class """
 17
 18    def __init__(self, width, height, title):
 19        super().__init__(width, height, title)
 20
 21        self.background_color = arcade.color.BLACK
 22
 23        self.frame_count = 0
 24        self.player_list = None
 25        self.enemy_list = None
 26        self.bullet_list = None
 27
 28        self.player = None
 29
 30    def setup(self):
 31        """ Setup the variables for the game. """
 32        self.player_list = arcade.SpriteList()
 33        self.enemy_list = arcade.SpriteList()
 34        self.bullet_list = arcade.SpriteList()
 35
 36        # Add player ship
 37        self.player = arcade.Sprite(":resources:images/space_shooter/playerShip1_orange.png", scale=0.5)
 38        self.player_list.append(self.player)
 39
 40        # Add top-left enemy ship
 41        enemy = arcade.Sprite(":resources:images/space_shooter/playerShip1_green.png", scale=0.5)
 42        enemy.center_x = 120
 43        enemy.center_y = SCREEN_HEIGHT - enemy.height
 44        enemy.angle = 180
 45        self.enemy_list.append(enemy)
 46
 47        # Add top-right enemy ship
 48        enemy = arcade.Sprite(":resources:images/space_shooter/playerShip1_green.png", scale=0.5)
 49        enemy.center_x = SCREEN_WIDTH - 120
 50        enemy.center_y = SCREEN_HEIGHT - enemy.height
 51        enemy.angle = 180
 52        self.enemy_list.append(enemy)
 53
 54    def on_draw(self):
 55        """Render the screen. """
 56
 57        self.clear()
 58
 59        self.enemy_list.draw()
 60        self.bullet_list.draw()
 61        self.player_list.draw()
 62
 63    def on_update(self, delta_time):
 64        """All the logic to move, and the game logic goes here. """
 65
 66        # Loop through each enemy that we have
 67        for enemy in self.enemy_list:
 68
 69            # Have a random 1 in 200 change of shooting each 1/60th of a second
 70            odds = 200
 71
 72            # Adjust odds based on delta-time
 73            adj_odds = int(odds * (1 / 60) / delta_time)
 74
 75            if random.randrange(adj_odds) == 0:
 76                bullet = arcade.Sprite(":resources:images/space_shooter/laserBlue01.png")
 77                bullet.center_x = enemy.center_x
 78                bullet.angle = 90
 79                bullet.top = enemy.bottom
 80                bullet.change_y = -2
 81                self.bullet_list.append(bullet)
 82
 83        # Get rid of the bullet when it flies off-screen
 84        for bullet in self.bullet_list:
 85            if bullet.top < 0:
 86                bullet.remove_from_sprite_lists()
 87
 88        self.bullet_list.update()
 89
 90    def on_mouse_motion(self, x, y, delta_x, delta_y):
 91        """ Called whenever the mouse moves. """
 92        self.player.center_x = x
 93        self.player.center_y = 20
 94
 95
 96def main():
 97    """ Main function """
 98    window = MyGame(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
 99    window.setup()
100    arcade.run()
101
102
103if __name__ == "__main__":
104    main()