# Falling Snow¶

snow.py
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 """ Simple Snow Based primarily on: http://arcade.academy/examples/sprite_collect_coins_move_down.html Contributed to Python Arcade Library by Nicholas Hartunian If Python and Arcade are installed, this example can be run from the command line with: python -m arcade.examples.snow """ import random import math import arcade SCREEN_WIDTH = 800 SCREEN_HEIGHT = 600 class Snowflake: """ Each instance of this class represents a single snowflake. Based on drawing filled-circles. """ def __init__(self): self.x = 0 self.y = 0 def reset_pos(self): # Reset flake to random position above screen self.y = random.randrange(SCREEN_HEIGHT, SCREEN_HEIGHT + 100) self.x = random.randrange(SCREEN_WIDTH) class MyGame(arcade.Window): """ Main application class. """ def __init__(self, width, height): """ Initializer :param width: :param height: """ # Calls "__init__" of parent class (arcade.Window) to setup screen super().__init__(width, height) # Sprite lists self.snowflake_list = None def start_snowfall(self): """ Set up snowfall and initialize variables. """ self.snowflake_list = [] for i in range(50): # Create snowflake instance snowflake = Snowflake() # Randomly position snowflake snowflake.x = random.randrange(SCREEN_WIDTH) snowflake.y = random.randrange(SCREEN_HEIGHT + 200) # Set other variables for the snowflake snowflake.size = random.randrange(4) snowflake.speed = random.randrange(20, 40) snowflake.angle = random.uniform(math.pi, math.pi * 2) # Add snowflake to snowflake list self.snowflake_list.append(snowflake) # Don't show the mouse pointer self.set_mouse_visible(False) # Set the background color arcade.set_background_color(arcade.color.BLACK) def on_draw(self): """ Render the screen. """ # This command is necessary before drawing arcade.start_render() # Draw the current position of each snowflake for snowflake in self.snowflake_list: arcade.draw_circle_filled(snowflake.x, snowflake.y, snowflake.size, arcade.color.WHITE) def update(self, delta_time): """ All the logic to move, and the game logic goes here. """ # Animate all the snowflakes falling for snowflake in self.snowflake_list: snowflake.y -= snowflake.speed * delta_time # Check if snowflake has fallen below screen if snowflake.y < 0: snowflake.reset_pos() # Some math to make the snowflakes move side to side snowflake.x += snowflake.speed * math.cos(snowflake.angle) * delta_time snowflake.angle += 1 * delta_time def main(): window = MyGame(SCREEN_WIDTH, SCREEN_HEIGHT) window.start_snowfall() arcade.run() if __name__ == "__main__": main()