Python Arcade – Adding Levels

In this article, we will learn how to add different levels to our arcade games in Python.

Adding Levels

We can easily add multiple levels to our Arcade game by following the below steps:

• Create a new variable to store the current level.

self.level = 1

• Load the sprites you are going to use in the current level with the help of self.level variable. For this example, we are going to load ‘Platform1’ named sprites for level 1, ‘Platform2’ named sprite for level 2, and so on.  For this, we can load the platforms using the below code.

platform = arcade.Sprite(f"Platform{self.level}.png", 1)

• If the player crosses the right side of the screen then we are going to increase the value of self.level variable to go to the next level.

 if self.player_sprite.center_x>690:
    self.level += 1

Functions Used:

• Camera(): The Camera class is used for controlling the visible viewport.

Syntax: arcade.Camera( width , height, window)

Parameters:

• width: width of the viewport
• height: height of the viewport
• window: Window to associate with this camera

• Scene(): A class that represents a scene object.

Syntax: arcade.Scene(sprite_lists , name_mapping)

Parameters:

• sprite_lists: A list of SpriteList objects
• name_mapping: A dictionary of SpriteList objects

• PhysicsEnginePlatformer(): Simplistic physics engine for use in a platformer.

Syntax: arcade.PhysicsEnginePlatformer( player_sprite , platforms, gravity, ladders)

Parameters:

• player_sprite: sprite of the player
• platforms: The sprites it can’t move through
• gravity: Downward acceleration per frame
• ladders: Ladders the user can climb on

Sprites Used:

In the below example, we are going to create a MainGame() class. Inside this class first, we are going to initialize some variables for velocity, camera, level, and player’s sprite then we will create 6 functions inside this class.

• on_draw(): Inside this function, we will use our camera and draw the scene.
• setup(): In this function, we will initialize our camera and scene object then we will load our player and platform’s sprites. After that, we will call the  PhysicsEnginePlatformer() function.
• on_update(): In this function, we will update the x coordinates of the player’s sprite, camera, and physics engine. We will also change our level in this function.
• on_key_press() and on_key_release(): In this function, we will change the value of the velocity variable according to the keyboard key that is pressed or released.
• camera_move(): In this function, we will move our camera according to our player’s current position.

Below is the implementation:

Python3

# Importing arcade module
import arcade

# Creating MainGame class
class MainGame(arcade.Window):
    def __init__(self):
        super().__init__(600, 600,
                         title = "Player Movement")

        # Initializing a variable to store
        # the velocity of the player
        self.vel_x = 0

        # Creating variable for Camera
        self.camera = None

        # Creating variable to store current level
        self.level = 1

        # Creating scene object
        self.scene = None

        # Creating variable to store player sprite
        self.player = None

        # Creating variable for our game engine
        self.physics_engine = None

    # Creating on_draw() function to draw on the screen
    def on_draw(self):
        arcade.start_render()

        # Using the camera
        self.camera.use()

        # Drawing our scene
        self.scene.draw()

    def setup(self):
         # Initialize Scene object
        self.scene = arcade.Scene()

        # Using Camera() function
        self.camera = arcade.Camera(600, 600)

        # Creating different sprite lists
        self.scene.add_sprite_list("Player")
        self.scene.add_sprite_list("Platforms",
                                   use_spatial_hash=True)

        # Adding player sprite
        self.player_sprite = arcade.Sprite("Player.png", 1)

        # Adding coordinates for the center of the sprite
        self.player_sprite.center_x = 64
        self.player_sprite.center_y = 600

        # Adding Sprite in our scene
        self.scene.add_sprite("Player", self.player_sprite)

        # Adding platform sprite according to level
        platform = arcade.Sprite(f"Platform{self.level}.png", 1)

        # Adding coordinates for the center of the platform
        platform.center_x = 300
        platform.center_y = 32
        self.scene.add_sprite("Platforms", platform)

        # Creating Physics engine
        self.physics_engine = arcade.PhysicsEnginePlatformer(
            self.player_sprite, self.scene.get_sprite_list("Platforms"), 0.5
        )

    # Creating on_update function to
    # update the x coordinate
    def on_update(self, delta_time):

        # Changing x coordinate of player
        self.player_sprite.center_x += self.vel_x * delta_time

        # Updating the physics engine to move the player
        self.physics_engine.update()

        # Calling the camera_move function
        self.camera_move()

        # Changing level if player crosses the right
        # end of screen
        if self.player_sprite.center_x > 690:
            self.level += 1
            self.setup()

    # Creating function to change the velocity
    # when button is pressed
    def on_key_press(self, symbol, modifier):

        # Checking the button pressed
        # and changing the value of velocity
        if symbol == arcade.key.LEFT:
            self.vel_x = -300
        elif symbol == arcade.key.RIGHT:
            self.vel_x = 300

    # Creating function to change the velocity
    # when button is released
    def on_key_release(self, symbol, modifier):

        # Checking the button released
        # and changing the value of velocity
        if symbol == arcade.key.LEFT:
            self.vel_x = 0
        elif symbol == arcade.key.RIGHT:
            self.vel_x = 0

    def camera_move(self):

        # Getting the x coordinate for the center of camera
        screen_x = self.player_sprite.center_x - \
            (self.camera.viewport_width / 2)

        # Getting the y coordinate for the center of camera
        screen_y = self.player_sprite.center_y - \
            (self.camera.viewport_height / 2)

        # Moving the camera
        self.camera.move_to([screen_x, screen_y])


# Calling MainGame class
game = MainGame()
game.setup()
arcade.run()

Output: