In this article, we will learn how to add ladders in Arcade using Python.
Adding Ladder
In this example, we are going to add one ladder on the screen which our player can climb. For this, we will use some functions:
draw_text(): This function is used to draw text to the screen using Pyglet’s label.
Syntax: arcade.draw_text(text, x, y, color, size, width, align, font_name)
Parameters:
- text: Text we want to display
- x : x coordinate
- y : y coordinate
- color : color of the text
- size : Size of the font
- width : Width of the text
- align : Alignment of the text
- font_name : Name of the font
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, scene, ladder sprite, and player’s sprite then we will create 4 functions inside this class.
- on_draw(): Inside this function, we will use our scene on the screen.
- setup(): In this function, we will initialize our scene object then we will load our player and platform’s sprites then we will load our ladder sprite and initialize the starting x and y coordinate. After that, we will call the PhysicsEnginePlatformer() function. We will pass our ladder as a parameter in our PhysicsEnginePlatformer() function.
- on_update(): In this function, we will update the physics engine and the x coordinates of the player’s sprite.
- 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.
Below is the implementation:
# 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 ladder sprite
self .ladder = 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()
# Drawing our scene
self .scene.draw()
def setup( self ):
# Initialize Scene object
self .scene = arcade.Scene()
# Loading ladder sprite
self .ladder = arcade.Sprite( "Ladder.png" , 1 )
# Initializing the starting coordinates
self .ladder.center_x = 500
self .ladder.center_y = 110
# Adding the ladder sprite in the scene
self .scene.add_sprite( "Ladder" , self .ladder)
# 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 = 90
# Adding Sprite in our scene
self .scene.add_sprite( "Player" , self .player_sprite)
# Adding platform sprite according to level
platform = arcade.Sprite(f "Platform.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 , self .scene.get_sprite_list( "Ladder" )
)
# 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()
# 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
elif symbol = = arcade.key.UP:
if self .physics_engine.is_on_ladder():
self .player_sprite.change_y = 2
elif self .physics_engine.can_jump():
self .player_sprite.change_y = 15
elif symbol = = arcade.key.DOWN:
if self .physics_engine.is_on_ladder():
self .player_sprite.change_y = - 2
# 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
elif symbol = = arcade.key.UP or symbol = = arcade.key.DOWN:
if self .physics_engine.is_on_ladder():
self .player_sprite.change_y = 0
# Calling MainGame class game = MainGame()
game.setup() arcade.run() |
Output: