Step 3 - Scene Object#
Next we will add a Scene to our game. A Scene is a tool to manage a number of different SpriteLists by assigning each one a name, and maintaining a draw order.
SpriteLists can be drawn directly like we saw in step 2 of this tutorial, but a Scene can be helpful to handle a lot of different lists at once and being able to draw them all with one call to the scene.
To start with we will remove our sprite lists from the __init__
function, and replace them
with a scene object.
"""
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
Next we will initialize the scene object in the setup
function and then add the SpriteLists to it
instead of creating new SpriteList objects directly.
Then instead of appending the Sprites to the SpriteLists directly, we can add them to the Scene and specify by name what SpriteList we want them added to.
self.player_sprite = None
self.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()
# Create the Sprite lists
self.scene.add_sprite_list("Player")
self.scene.add_sprite_list("Walls", use_spatial_hash=True)
# 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(
Lastly in our on_draw
function we can draw the scene.
)
wall.position = coordinate
self.scene.add_sprite("Walls", wall)
def on_draw(self):
"""Render the screen."""
# Clear the screen to the background color
Source Code#
1"""
2Platformer Game
3
4python -m arcade.examples.platform_tutorial.03_scene_object
5"""
6from __future__ import annotations
7
8import arcade
9
10# Constants
11SCREEN_WIDTH = 1000
12SCREEN_HEIGHT = 650
13SCREEN_TITLE = "Platformer"
14
15# Constants used to scale our sprites from their original size
16CHARACTER_SCALING = 1
17TILE_SCALING = 0.5
18
19
20class MyGame(arcade.Window):
21 """
22 Main application class.
23 """
24
25 def __init__(self):
26
27 # Call the parent class and set up the window
28 super().__init__(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
29
30 # Our Scene Object
31 self.scene = None
32
33 # Separate variable that holds the player sprite
34 self.player_sprite = None
35
36 self.background_color = arcade.csscolor.CORNFLOWER_BLUE
37
38 def setup(self):
39 """Set up the game here. Call this function to restart the game."""
40
41 # Initialize Scene
42 self.scene = arcade.Scene()
43
44 # Create the Sprite lists
45 self.scene.add_sprite_list("Player")
46 self.scene.add_sprite_list("Walls", use_spatial_hash=True)
47
48 # Set up the player, specifically placing it at these coordinates.
49 image_source = ":resources:images/animated_characters/female_adventurer/femaleAdventurer_idle.png"
50 self.player_sprite = arcade.Sprite(image_source, CHARACTER_SCALING)
51 self.player_sprite.center_x = 64
52 self.player_sprite.center_y = 128
53 self.scene.add_sprite("Player", self.player_sprite)
54
55 # Create the ground
56 # This shows using a loop to place multiple sprites horizontally
57 for x in range(0, 1250, 64):
58 wall = arcade.Sprite(":resources:images/tiles/grassMid.png", TILE_SCALING)
59 wall.center_x = x
60 wall.center_y = 32
61 self.scene.add_sprite("Walls", wall)
62
63 # Put some crates on the ground
64 # This shows using a coordinate list to place sprites
65 coordinate_list = [[512, 96], [256, 96], [768, 96]]
66
67 for coordinate in coordinate_list:
68 # Add a crate on the ground
69 wall = arcade.Sprite(
70 ":resources:images/tiles/boxCrate_double.png", TILE_SCALING
71 )
72 wall.position = coordinate
73 self.scene.add_sprite("Walls", wall)
74
75 def on_draw(self):
76 """Render the screen."""
77
78 # Clear the screen to the background color
79 self.clear()
80
81 # Draw our Scene
82 self.scene.draw()
83
84
85def main():
86 """Main function"""
87 window = MyGame()
88 window.setup()
89 arcade.run()
90
91
92if __name__ == "__main__":
93 main()