Have Enemies Aim at Player¶
sprite_bullets_enemy_aims.py¶
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Show how to have enemies shoot bullets aimed at the player.
"""
import arcade
import math
SCREEN_WIDTH = 800
SCREEN_HEIGHT = 600
BULLET_SPEED = 4
class MyApplication(arcade.Window):
""" Main application class """
def __init__(self, width, height):
super().__init__(width, height)
arcade.set_background_color(arcade.color.BLACK)
self.frame_count = 0
self.all_sprites_list = arcade.SpriteList()
self.enemy_list = arcade.SpriteList()
self.bullet_list = arcade.SpriteList()
self.player = arcade.Sprite("images/playerShip1_orange.png", 0.5)
self.all_sprites_list.append(self.player)
enemy = arcade.Sprite("images/playerShip1_green.png", 0.5)
enemy.center_x = 120
enemy.center_y = SCREEN_HEIGHT - enemy.height
enemy.angle = 180
self.all_sprites_list.append(enemy)
self.enemy_list.append(enemy)
enemy = arcade.Sprite("images/playerShip1_green.png", 0.5)
enemy.center_x = SCREEN_WIDTH - 120
enemy.center_y = SCREEN_HEIGHT - enemy.height
enemy.angle = 180
self.all_sprites_list.append(enemy)
self.enemy_list.append(enemy)
def on_draw(self):
"""Render the screen. """
arcade.start_render()
self.all_sprites_list.draw()
def update(self, delta_time):
"""All the logic to move, and the game logic goes here. """
self.frame_count += 1
for enemy in self.enemy_list:
# First, calculate the angle to the player. We could do this
# only when the bullet fires, but in this case we will rotate
# the enemy to face the player each frame, so we'll do this
# each frame.
# Position the start at the enemy's current location
start_x = enemy.center_x
start_y = enemy.center_y
# Get the destination location for the bullet
dest_x = self.player.center_x
dest_y = self.player.center_y
# Do math to calculate how to get the bullet to the destination.
# Calculation the angle in radians between the start points
# and end points. This is the angle the bullet will travel.
x_diff = dest_x - start_x
y_diff = dest_y - start_y
angle = math.atan2(y_diff, x_diff)
# Set the enemy to face the player.
enemy.angle = math.degrees(angle)-90
# Shoot every 60 frames change of shooting each frame
if self.frame_count % 60 == 0:
bullet = arcade.Sprite("images/laserBlue01.png")
bullet.center_x = start_x
bullet.center_y = start_y
# Angle the bullet sprite
bullet.angle = math.degrees(angle)
# Taking into account the angle, calculate our change_x
# and change_y. Velocity is how fast the bullet travels.
bullet.change_x = math.cos(angle) * BULLET_SPEED
bullet.change_y = math.sin(angle) * BULLET_SPEED
self.bullet_list.append(bullet)
self.all_sprites_list.append(bullet)
# Get rid of the bullet when it flies off-screen
for bullet in self.bullet_list:
if bullet.top < 0:
bullet.kill()
self.bullet_list.update()
def on_mouse_motion(self, x, y, delta_x, delta_y):
"""Called whenever the mouse moves. """
self.player.center_x = x
self.player.center_y = y
window = MyApplication(SCREEN_WIDTH, SCREEN_HEIGHT)
arcade.run()
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