``` 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``` ```""" This animation example shows how perform a radar sweep animation. If Python and Arcade are installed, this example can be run from the command line with: python -m arcade.examples.radar_sweep """ import arcade import math # Set up the constants SCREEN_WIDTH = 800 SCREEN_HEIGHT = 600 SCREEN_TITLE = "Radar Sweep Example" # These constants control the particulars about the radar CENTER_X = SCREEN_WIDTH // 2 CENTER_Y = SCREEN_HEIGHT // 2 RADIANS_PER_FRAME = 0.02 SWEEP_LENGTH = 250 class Radar: def __init__(self): self.angle = 0 def update(self): # Move the angle of the sweep. self.angle += RADIANS_PER_FRAME def draw(self): """ Use this function to draw everything to the screen. """ # Calculate the end point of our radar sweep. Using math. x = SWEEP_LENGTH * math.sin(self.angle) + CENTER_X y = SWEEP_LENGTH * math.cos(self.angle) + CENTER_Y # Start the render. This must happen before any drawing # commands. We do NOT need an stop render command. arcade.start_render() # Draw the radar line arcade.draw_line(CENTER_X, CENTER_Y, x, y, arcade.color.OLIVE, 4) # Draw the outline of the radar arcade.draw_circle_outline(CENTER_X, CENTER_Y, SWEEP_LENGTH, arcade.color.DARK_GREEN, border_width=10, num_segments=60) class MyGame(arcade.Window): """ Main application class. """ def __init__(self, width, height, title): super().__init__(width, height, title) # Create our rectangle self.radar = Radar() # Set background color arcade.set_background_color(arcade.color.BLACK) def on_update(self, delta_time): # Move the rectangle self.radar.update() def on_draw(self): """ Render the screen. """ # Clear screen self.clear() # Draw the rectangle self.radar.draw() def main(): """ Main function """ MyGame(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE) arcade.run() if __name__ == "__main__": main() ```