Arcade官方教程解析 3 Add User Control

"""
Platformer Game
"""
import arcade

# Constants
SCREEN_WIDTH = 1000
SCREEN_HEIGHT = 650
SCREEN_TITLE = "Platformer"

# Constants used to scale our sprites from their original size
CHARACTER_SCALING = 1
TILE_SCALING = 0.5


# Movement speed of player, in pixels per frame

PLAYER_MOVEMENT_SPEED = 5



class MyGame(arcade.Window):
    """
    Main application class.
    """

    def __init__(self):

        # Call the parent class and set up the window
        super().__init__(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)

        # Our Scene Object
        self.scene = None

        # Separate variable that holds the player sprite
        self.player_sprite = None


        # Our physics engine

        self.physics_engine = None


        arcade.set_background_color(arcade.csscolor.CORNFLOWER_BLUE)

    def setup(self):
        """Set up the game here. Call this function to restart the game."""

        # Initialize Scene
        self.scene = arcade.Scene()

        # Set up the player, specifically placing it at these coordinates.
        image_source = ":resources:images/animated_characters/female_adventurer/femaleAdventurer_idle.png"
        self.player_sprite = arcade.Sprite(image_source, CHARACTER_SCALING)
        self.player_sprite.center_x = 64
        self.player_sprite.center_y = 128
        self.scene.add_sprite("Player", self.player_sprite)

        # Create the ground
        # This shows using a loop to place multiple sprites horizontally
        for x in range(0, 1250, 64):
            wall = arcade.Sprite(":resources:images/tiles/grassMid.png", TILE_SCALING)
            wall.center_x = x
            wall.center_y = 32
            self.scene.add_sprite("Walls", wall)

        # Put some crates on the ground
        # This shows using a coordinate list to place sprites
        coordinate_list = [[512, 96], [256, 96], [768, 96]]

        for coordinate in coordinate_list:
            # Add a crate on the ground
            wall = arcade.Sprite(
                ":resources:images/tiles/boxCrate_double.png", TILE_SCALING
            )
            wall.position = coordinate
            self.scene.add_sprite("Walls", wall)


        # Create the 'physics engine'
        # 实例化一个物理引擎，将player和walls加入其中

        self.physics_engine = arcade.PhysicsEngineSimple(

            self.player_sprite, self.scene.get_sprite_list("Walls")

        )


    def on_draw(self):
        """Render the screen."""

        # Clear the screen to the background color
        self.clear()

        # Draw our Scene
        self.scene.draw()

    # 添加控制事件
    def on_key_press(self, key, modifiers):

        """Called whenever a key is pressed."""



        if key == arcade.key.UP or key == arcade.key.W:

            self.player_sprite.change_y = PLAYER_MOVEMENT_SPEED

        elif key == arcade.key.DOWN or key == arcade.key.S:

            self.player_sprite.change_y = -PLAYER_MOVEMENT_SPEED

        elif key == arcade.key.LEFT or key == arcade.key.A:

            self.player_sprite.change_x = -PLAYER_MOVEMENT_SPEED

        elif key == arcade.key.RIGHT or key == arcade.key.D:

            self.player_sprite.change_x = PLAYER_MOVEMENT_SPEED

    # 添加控制事件
    def on_key_release(self, key, modifiers):

        """Called when the user releases a key."""



        if key == arcade.key.UP or key == arcade.key.W:

            self.player_sprite.change_y = 0

        elif key == arcade.key.DOWN or key == arcade.key.S:

            self.player_sprite.change_y = 0

        elif key == arcade.key.LEFT or key == arcade.key.A:

            self.player_sprite.change_x = 0

        elif key == arcade.key.RIGHT or key == arcade.key.D:

            self.player_sprite.change_x = 0



    def on_update(self, delta_time):

        """Movement and game logic"""



        # Move the player with the physics engine

        self.physics_engine.update()



def main():
    """Main function"""
    window = MyGame()
    window.setup()
    arcade.run()


if __name__ == "__main__":
    main()
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这是一个平台游戏的主程序。在这个游戏中，玩家可以使用键盘控制角色的移动。

首先，我们导入了arcade模块来构建游戏。

接下来，我们定义了一些常量，包括屏幕的宽度和高度以及游戏的标题。

然后，我们定义了一个MyGame类，继承自arcade.Window类。这个类是我们的主应用程序类，负责设置游戏并处理用户输入。

在__init__方法中，我们首先调用父类的__init__方法来设置窗口的大小和标题。然后，我们初始化场景对象和玩家精灵对象，并设置背景颜色。

在setup方法中，我们设置了游戏的初始状态。我们创建了一个场景对象，并在场景中添加了玩家精灵和地面精灵。然后，我们创建了一个物理引擎，并将玩家精灵和地面精灵添加到物理引擎中。

在on_draw方法中，我们清空屏幕，并绘制场景。

on_key_press和on_key_release方法分别处理按键按下和释放的事件。根据按下或释放的键位，我们改变玩家精灵的速度，从而实现角色的移动。

on_update方法用于更新游戏逻辑。在这个方法中，我们使用物理引擎来移动玩家精灵。

最后，我们定义了一个main函数，在其中创建了MyGame实例，并调用setup方法。然后，我们调用arcade.run()来启动游戏循环。

如果在执行这个文件时，将会运行这个main函数。