Bouncing Rectangle#

This shows how to animate an item you can draw using the drawing primitives.

../../_images/bouncing_rectangle.png
bouncing_rectangle.py#
  1"""
  2This simple animation example shows how to bounce a rectangle
  3on the screen.
  4
  5If Python and Arcade are installed, this example can be run
  6from the command line with:
  7python -m arcade.examples.bouncing_rectangle
  8"""
  9
 10from __future__ import annotations
 11
 12import arcade
 13
 14# --- Set up the constants
 15
 16# Size of the screen
 17SCREEN_WIDTH = 600
 18SCREEN_HEIGHT = 600
 19SCREEN_TITLE = "Bouncing Rectangle Example"
 20
 21# Rectangle info
 22RECT_WIDTH = 50
 23RECT_HEIGHT = 50
 24RECT_COLOR = arcade.color.DARK_BROWN
 25
 26BACKGROUND_COLOR = arcade.color.ALMOND
 27
 28
 29class Item:
 30    """ This class represents our rectangle """
 31
 32    def __init__(self):
 33
 34        # Set up attribute variables
 35
 36        # Where we are
 37        self.center_x = 0
 38        self.center_y = 0
 39
 40        # Where we are going
 41        self.change_x = 0
 42        self.change_y = 0
 43
 44    def update(self):
 45        # Move the rectangle
 46        self.center_x += self.change_x
 47        self.center_y += self.change_y
 48        # Check if we need to bounce of right edge
 49        if self.center_x > SCREEN_WIDTH - RECT_WIDTH / 2:
 50            self.change_x *= -1
 51        # Check if we need to bounce of top edge
 52        if self.center_y > SCREEN_HEIGHT - RECT_HEIGHT / 2:
 53            self.change_y *= -1
 54        # Check if we need to bounce of left edge
 55        if self.center_x < RECT_WIDTH / 2:
 56            self.change_x *= -1
 57        # Check if we need to bounce of bottom edge
 58        if self.center_y < RECT_HEIGHT / 2:
 59            self.change_y *= -1
 60
 61    def draw(self):
 62        # Draw the rectangle
 63        arcade.draw_rectangle_filled(self.center_x,
 64                                     self.center_y,
 65                                     RECT_WIDTH,
 66                                     RECT_HEIGHT,
 67                                     RECT_COLOR)
 68
 69
 70class MyGame(arcade.Window):
 71    """ Main application class. """
 72
 73    def __init__(self, width, height, title):
 74        super().__init__(width, height, title)
 75
 76        # Create our rectangle
 77        self.item = Item()
 78        self.item.center_x = 200
 79        self.item.center_y = 300
 80        self.item.change_x = 2
 81        self.item.change_y = 3
 82
 83        # Set background color
 84        self.background_color = BACKGROUND_COLOR
 85
 86    def on_update(self, delta_time):
 87        # Move the rectangle
 88        self.item.update()
 89
 90    def on_draw(self):
 91        """ Render the screen. """
 92
 93        # Clear screen
 94        self.clear()
 95        # Draw the rectangle
 96        self.item.draw()
 97
 98
 99def main():
100    """ Main function """
101    MyGame(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
102    arcade.run()
103
104
105if __name__ == "__main__":
106    main()