Move with a Scrolling Screen¶
sprite_move_scrolling.py¶
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Use sprites to scroll around a large screen.
Simple program to show basic sprite usage.
Artwork from http://kenney.nl
If Python and Arcade are installed, this example can be run from the command line with:
python -m arcade.examples.sprite_move_scrolling
"""
import random
import arcade
import os
SPRITE_SCALING = 0.5
SCREEN_WIDTH = 800
SCREEN_HEIGHT = 600
SCREEN_TITLE = "Sprite Move with Scrolling Screen Example"
# How many pixels to keep as a minimum margin between the character
# and the edge of the screen.
VIEWPORT_MARGIN = 40
MOVEMENT_SPEED = 5
class MyGame(arcade.Window):
""" Main application class. """
def __init__(self, width, height, title):
"""
Initializer
"""
super().__init__(width, height, title)
# Set the working directory (where we expect to find files) to the same
# directory this .py file is in. You can leave this out of your own
# code, but it is needed to easily run the examples using "python -m"
# as mentioned at the top of this program.
file_path = os.path.dirname(os.path.abspath(__file__))
os.chdir(file_path)
# Sprite lists
self.player_list = None
# Set up the player
self.player_sprite = None
self.coin_list = None
self.wall_list = None
self.physics_engine = None
# Used in scrolling
self.view_bottom = 0
self.view_left = 0
def setup(self):
""" Set up the game and initialize the variables. """
# Sprite lists
self.player_list = arcade.SpriteList()
self.wall_list = arcade.SpriteList()
# Set up the player
self.player_sprite = arcade.Sprite(":resources:images/animated_characters/female_person/femalePerson_idle.png", 0.4)
self.player_sprite.center_x = 64
self.player_sprite.center_y = 270
self.player_list.append(self.player_sprite)
# -- Set up several columns of walls
for x in range(200, 1650, 210):
for y in range(0, 1000, 64):
# Randomly skip a box so the player can find a way through
if random.randrange(5) > 0:
wall = arcade.Sprite(":resources:images/tiles/boxCrate_double.png", SPRITE_SCALING)
wall.center_x = x
wall.center_y = y
self.wall_list.append(wall)
self.physics_engine = arcade.PhysicsEngineSimple(self.player_sprite, self.wall_list)
# Set the background color
arcade.set_background_color(arcade.color.AMAZON)
# Set the viewport boundaries
# These numbers set where we have 'scrolled' to.
self.view_left = 0
self.view_bottom = 0
def on_draw(self):
"""
Render the screen.
"""
# This command has to happen before we start drawing
arcade.start_render()
# Draw all the sprites.
self.wall_list.draw()
self.player_list.draw()
def on_key_press(self, key, modifiers):
"""Called whenever a key is pressed. """
if key == arcade.key.UP:
self.player_sprite.change_y = MOVEMENT_SPEED
elif key == arcade.key.DOWN:
self.player_sprite.change_y = -MOVEMENT_SPEED
elif key == arcade.key.LEFT:
self.player_sprite.change_x = -MOVEMENT_SPEED
elif key == arcade.key.RIGHT:
self.player_sprite.change_x = MOVEMENT_SPEED
def on_key_release(self, key, modifiers):
"""Called when the user releases a key. """
if key == arcade.key.UP or key == arcade.key.DOWN:
self.player_sprite.change_y = 0
elif key == arcade.key.LEFT or key == arcade.key.RIGHT:
self.player_sprite.change_x = 0
def on_update(self, delta_time):
""" Movement and game logic """
# Call update on all sprites (The sprites don't do much in this
# example though.)
self.physics_engine.update()
# --- Manage Scrolling ---
# Keep track of if we changed the boundary. We don't want to call the
# set_viewport command if we didn't change the view port.
changed = False
# Scroll left
left_boundary = self.view_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 - 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 - 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 + VIEWPORT_MARGIN
if self.player_sprite.bottom < bottom_boundary:
self.view_bottom -= bottom_boundary - self.player_sprite.bottom
changed = True
# Make sure our boundaries are integer values. While the view port does
# support floating point numbers, for this application we want every pixel
# in the view port to map directly onto a pixel on the screen. We don't want
# any rounding errors.
self.view_left = int(self.view_left)
self.view_bottom = int(self.view_bottom)
# If we changed the boundary values, update the view port to match
if changed:
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(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
window.setup()
arcade.run()
if __name__ == "__main__":
main()
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