Step 6 - Add Coins And Sound

../../_images/listing_06.png

The code below adds coins that we can collect. It also adds a sound to be played when the user hits a coin, or presses the jump button.

We check to see if the user hits a coin by the arcade.check_for_collision_with_list function. Just pass the player sprite, along with a SpriteList that holds the coins. The function returns a list of coins in contact with the player sprite. If no coins are in contact, the list is empty.

The method Sprite.remove_from_sprite_lists will remove that sprite from all lists, and effectively the game.

Notice that any transparent “white-space” around the image counts as the hitbox. You can trim the space in a graphics editor, or in the second section, we’ll show you how to specify the hitbox.

Add Coins and Sound
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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

# How many pixels to keep as a minimum margin between the character
# and the edge of the screen.
LEFT_VIEWPORT_MARGIN = 250
RIGHT_VIEWPORT_MARGIN = 250
BOTTOM_VIEWPORT_MARGIN = 50
TOP_VIEWPORT_MARGIN = 100


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)

        # These are 'lists' that keep track of our sprites. Each sprite should
        # go into a list.
        self.coin_list = None
        self.wall_list = None
        self.player_list = None

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

        # Our physics engine
        self.physics_engine = None

        # Used to keep track of our scrolling
        self.view_bottom = 0
        self.view_left = 0

        # 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. """

        # Used to keep track of our scrolling
        self.view_bottom = 0
        self.view_left = 0

        # Create the Sprite lists
        self.player_list = arcade.SpriteList()
        self.wall_list = arcade.SpriteList()
        self.coin_list = arcade.SpriteList()

        # 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.player_list.append(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.wall_list.append(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.wall_list.append(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.coin_list.append(coin)

        # Create the 'physics engine'
        self.physics_engine = arcade.PhysicsEnginePlatformer(self.player_sprite,
                                                             self.wall_list,
                                                             GRAVITY)

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

        # Clear the screen to the background color
        arcade.start_render()

        # Draw our sprites
        self.wall_list.draw()
        self.coin_list.draw()
        self.player_list.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 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.coin_list)

        # 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)

        # --- Manage Scrolling ---

        # Track if we need to change the viewport

        changed = False

        # Scroll left
        left_boundary = self.view_left + LEFT_VIEWPORT_MARGIN
        if self.player_sprite.left < left_boundary:
            self.view_left -= left_boundary - self.player_sprite.left
            changed = True

        # Scroll right
        right_boundary = self.view_left + SCREEN_WIDTH - RIGHT_VIEWPORT_MARGIN
        if self.player_sprite.right > right_boundary:
            self.view_left += self.player_sprite.right - right_boundary
            changed = True

        # Scroll up
        top_boundary = self.view_bottom + SCREEN_HEIGHT - TOP_VIEWPORT_MARGIN
        if self.player_sprite.top > top_boundary:
            self.view_bottom += self.player_sprite.top - top_boundary
            changed = True

        # Scroll down
        bottom_boundary = self.view_bottom + BOTTOM_VIEWPORT_MARGIN
        if self.player_sprite.bottom < bottom_boundary:
            self.view_bottom -= bottom_boundary - self.player_sprite.bottom
            changed = True

        if changed:
            # Only scroll to integers. Otherwise we end up with pixels that
            # don't line up on the screen
            self.view_bottom = int(self.view_bottom)
            self.view_left = int(self.view_left)

            # Do the scrolling
            arcade.set_viewport(self.view_left,
                                SCREEN_WIDTH + self.view_left,
                                self.view_bottom,
                                SCREEN_HEIGHT + self.view_bottom)


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


if __name__ == "__main__":
    main()

Note

Spend time placing the coins where you would like them. If you have extra time, try adding more than just coins. Also add gems or keys from the graphics provided.

You could also subclass the coin sprite and add an attribute for a score value. Then you could have coins worth one point, and gems worth 5, 10, and 15 points.