步骤7-添加硬币和声音#

../../_images/title_07.png

接下来，我们将添加一些玩家可以拾取的硬币。我们还将添加一个声音，当他们拿起它时播放，以及当他们跳跃时的声音。

将硬币添加到场景中#

首先，我们需要将硬币添加到场景中。让我们首先在应用程序的顶部添加一个常量，用于Coin Sprite缩放，类似于我们的 TILE_SCALING 一。

添加硬币和声音#
COIN_SCALING = 0.5

接下来是我们的 setup 函数我们可以使用for循环创建我们的硬币，就像我们之前对地面所做的那样，然后将它们添加到场景中。

添加硬币和声音#
        # Use a loop to place some coins for our character to pick up
        for x in range(128, 1250, 256):
            coin = arcade.Sprite(":resources:images/items/coinGold.png", COIN_SCALING)
            coin.center_x = x
            coin.center_y = 96
            self.scene.add_sprite("Coins", coin)

加载声音#

现在我们可以加载我们的声音来收集硬币和跳跃。稍后，我们将使用这些变量在特定事件发生时播放声音。将以下内容添加到 __init__ 加载声音的函数：

添加硬币和声音#
        # Load sounds
        self.collect_coin_sound = arcade.load_sound(":resources:sounds/coin1.wav")
        self.jump_sound = arcade.load_sound(":resources:sounds/jump1.wav")

然后，我们可以在玩家跳跃时播放跳跃声音，方法是将它添加到 on_key_press 功能：

添加硬币和声音#
    def on_key_press(self, key, modifiers):
        """Called whenever a key is pressed."""

        if key == arcade.key.UP or key == arcade.key.W:
            if self.physics_engine.can_jump():
                self.player_sprite.change_y = PLAYER_JUMP_SPEED
                arcade.play_sound(self.jump_sound)
        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

碰撞检测#

最后，我们需要找出玩家是否击中了硬币。我们可以在我们的 on_update 函数通过使用 arcade.check_for_collision_with_list 功能。我们可以传递玩家精灵，以及一个 SpriteList 用来装硬币的。该函数将返回玩家当前正在与之碰撞的硬币列表。如果接触中没有硬币，则列表将为空。

然后，我们可以使用 Sprite.remove_from_sprite_lists 该函数会将给定的精灵从其所属的任何SpriteList中删除，从而有效地将其从游戏中删除。

注解

请注意，图像周围的任何透明“空白”都算作Hitbox。您可以在图形编辑器中修剪空间，或者稍后，我们将介绍如何自定义Sprite的Hitbox。

将以下内容添加到 on_update 当玩家拿起硬币时，添加碰撞检测和播放声音的功能。

添加硬币和声音#
        # See if we hit any coins
        coin_hit_list = arcade.check_for_collision_with_list(
            self.player_sprite, self.scene["Coins"]
        )

        # Loop through each coin we hit (if any) and remove it
        for coin in coin_hit_list:
            # Remove the coin
            coin.remove_from_sprite_lists()
            # Play a sound
            arcade.play_sound(self.collect_coin_sound)

注解

花点时间把硬币放在你喜欢的地方。如果你有额外的时间，试着添加更多的硬币。还可以从提供的图形中添加宝石或钥匙。

您还可以将硬币精灵细分为子类，并为分值添加一个属性。然后你可以拥有价值1分的硬币，以及价值5分、10分和15分的宝石。

源代码#

添加硬币和声音#
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"""
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
COIN_SCALING = 0.5

# Movement speed of player, in pixels per frame
PLAYER_MOVEMENT_SPEED = 5
GRAVITY = 1
PLAYER_JUMP_SPEED = 20


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

        # A Camera that can be used for scrolling the screen
        self.camera = None

        # Load sounds
        self.collect_coin_sound = arcade.load_sound(":resources:sounds/coin1.wav")
        self.jump_sound = arcade.load_sound(":resources:sounds/jump1.wav")

        arcade.set_background_color(arcade.csscolor.CORNFLOWER_BLUE)

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

        # Set up the Camera
        self.camera = arcade.Camera(self.width, self.height)

        # 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)

        # Use a loop to place some coins for our character to pick up
        for x in range(128, 1250, 256):
            coin = arcade.Sprite(":resources:images/items/coinGold.png", COIN_SCALING)
            coin.center_x = x
            coin.center_y = 96
            self.scene.add_sprite("Coins", coin)

        # Create the 'physics engine'
        self.physics_engine = arcade.PhysicsEnginePlatformer(
            self.player_sprite, gravity_constant=GRAVITY, walls=self.scene["Walls"]
        )

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

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

        # Activate our Camera
        self.camera.use()

        # Draw our Scene
        self.scene.draw()

    def on_key_press(self, key, modifiers):
        """Called whenever a key is pressed."""

        if key == arcade.key.UP or key == arcade.key.W:
            if self.physics_engine.can_jump():
                self.player_sprite.change_y = PLAYER_JUMP_SPEED
                arcade.play_sound(self.jump_sound)
        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

    def on_key_release(self, key, modifiers):
        """Called when the user releases a key."""

        if 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 center_camera_to_player(self):
        screen_center_x = self.player_sprite.center_x - (self.camera.viewport_width / 2)
        screen_center_y = self.player_sprite.center_y - (
            self.camera.viewport_height / 2
        )
        if screen_center_x < 0:
            screen_center_x = 0
        if screen_center_y < 0:
            screen_center_y = 0
        player_centered = screen_center_x, screen_center_y

        self.camera.move_to(player_centered)

    def on_update(self, delta_time):
        """Movement and game logic"""

        # Move the player with the physics engine
        self.physics_engine.update()

        # See if we hit any coins
        coin_hit_list = arcade.check_for_collision_with_list(
            self.player_sprite, self.scene["Coins"]
        )

        # Loop through each coin we hit (if any) and remove it
        for coin in coin_hit_list:
            # Remove the coin
            coin.remove_from_sprite_lists()
            # Play a sound
            arcade.play_sound(self.collect_coin_sound)

        # Position the camera
        self.center_camera_to_player()


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


if __name__ == "__main__":
    main()