Have Enemies Randomly Shoot#
Having enemies randomly shoot is easier than periodically shooting enemies as shown in Have Enemies Periodically Shoot. This is because we don’t have to track how long it has been since we last fired.
See the highlighted lines for what is specific to this example.
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()