arcade敌人朝飞船射击示例

"""
显示如何让敌人朝飞船射击
Show how to have enemies shoot bullets aimed at the player.
 
"""

import arcade
import math
import os

SCREEN_WIDTH = 800
SCREEN_HEIGHT = 600
SCREEN_TITLE = "arcade敌人朝飞船射击示例"
BULLET_SPEED = 4

class MyGame(arcade.Window):
    """ 主要应用程序类 """

    def __init__(self, width, height, title):
        super().__init__(width, height, title)

        # 设置工作目录 for python -m而设
        file_path = os.path.dirname(os.path.abspath(__file__))
        os.chdir(file_path)

        arcade.set_background_color(arcade.color.BLACK) # 设置背景颜色

        self.frame_count = 0  # 帧计数器

        self.enemy_list = None
        self.bullet_list = None
        self.player_list = None
        self.player = None

    def setup(self):
        self.enemy_list = arcade.SpriteList()   # 敌人列表
        self.bullet_list = arcade.SpriteList()  # 子弹列表
        self.player_list = arcade.SpriteList()  # 玩家列表

        # 实例化玩家操作的飞船
        self.player = arcade.Sprite("images/playerShip1_orange.png", 0.5)
        self.player_list.append(self.player)

        # 实例化左上角敌人
        enemy = arcade.Sprite("images/playerShip1_green.png", 0.5)
        enemy.center_x = 120
        enemy.center_y = SCREEN_HEIGHT - enemy.height
        enemy.angle = 180
        self.enemy_list.append(enemy)

        # 实例化右上角敌人
        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.enemy_list.append(enemy)

    def on_draw(self):
        """渲染屏幕. """

        arcade.start_render()

        self.enemy_list.draw()  # 重画所有敌人
        self.bullet_list.draw() # 重画所有子弹
        self.player_list.draw() # 重画所有玩家飞船

    def update(self, delta_time):
        """移动所有角色与游戏逻辑代码. """

        self.frame_count += 1  # 帧计数

        # 遍历每个敌人
        for enemy in self.enemy_list:

            # 首先,计算到玩家的角度. 我们可以当发射时才计算,但是这里要让敌人
            # 实时地面向玩家飞船,所以每帧都计算。

            # 起点就是敌人的坐标
            start_x = enemy.center_x
            start_y = enemy.center_y

            # 终点就是飞船的坐标
            dest_x = self.player.center_x
            dest_y = self.player.center_y

            # 用反正切函数计算朝向角度.
            x_diff = dest_x - start_x
            y_diff = dest_y - start_y
            angle = math.atan2(y_diff, x_diff)

            # 设置角度
            enemy.angle = math.degrees(angle)-90

            # 每60帧发射一次,约1秒
            if self.frame_count % 60 == 0:
                bullet = arcade.Sprite("images/laserBlue01.png")
                bullet.center_x = start_x
                bullet.center_y = start_y

                # 子弹射击角度转换为度数表示
                bullet.angle = math.degrees(angle)

                # 设置速度向量
                bullet.change_x = math.cos(angle) * BULLET_SPEED
                bullet.change_y = math.sin(angle) * BULLET_SPEED

                self.bullet_list.append(bullet)

        # 子弹的顶y坐标小于0就杀死它
        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):
        """鼠标指针控制玩家. """
        self.player.center_x = x
        self.player.center_y = y


def main():
    """ Main method """
    window = MyGame(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
    window.setup()
    arcade.run()


if __name__ == "__main__":
    main()