Your Own Function

Part of the Python in a Game Window section of Coddy's Pygame journey. Lesson 20 of 32.

A function is a named group of lines you can run whenever you want. def makes one:

def draw_star():
    pygame.draw.line(screen, (255, 240, 200), (310, 240), (330, 240), 2)
    pygame.draw.line(screen, (255, 240, 200), (320, 230), (320, 250), 2)
    pygame.draw.circle(screen, (255, 240, 200), (320, 240), 4)

def, the name, round brackets and a colon; the body is indented under it. Defining a function draws nothing: Python only remembers the lines under the name.

To run them, call the function: write its name with brackets.

draw_star()

Define functions in the setup part, before the game loop, and call them in the loop where you need them. You have called functions since the first lesson: print() and pygame.draw.circle() are functions too, written by others.

pygame.draw.line(screen, colour, start, end, width) draws a line between two points.

Challenge

Medium

Put the star in a function:

In the setup part, make def draw_star(): and move the three star lines into its body.
In the draw part, call draw_star(). The star shows at (320, 240) as before.

Try it yourself

import pygame

pygame.init()
screen = pygame.display.set_mode((640, 480))
pygame.display.set_caption("Night Sky")
clock = pygame.time.Clock()

# Set things up here, before the game loop.

running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

    # Change things here, once a frame.

    screen.fill((20, 24, 48))
    # Draw here, after the fill.
    pygame.draw.line(screen, (255, 240, 200), (310, 240), (330, 240), 2)
    pygame.draw.line(screen, (255, 240, 200), (320, 230), (320, 250), 2)
    pygame.draw.circle(screen, (255, 240, 200), (320, 240), 4)

    pygame.display.flip()
    clock.tick(60)

pygame.quit()