Lists in Pygame

Goals

• Make use of lists to store the locations of multiple objects.

• Save some squares in a list

• Draw the squares on the screen

• Add squares by clicking the locations

Starter code

• Pygame Template

What you need to do

1. Better drawing - use pygame.mouse.get_pressed() to check each frame, in game state updates, if a mouse buttin is currently being pressed. Then if it is, get the mouse position with pygame.mouse.get_pos() and draw a square there.

2. Timed squares - Create a variable to record the frame count. In the loop do frame count += 1. If the frame count is divisible by 30 (frames % 30 == 0), random x and y and add that “square” to the list.

3. Move the squares - In the game updates create another loop to change the squares x and y position.

4. ADVANCED Square defense - Separate the randomized moving squares (the enemies) and the user click-generated squares (defenders) into different lists. When an enemy and a defender overlap, they both dissappear. If an enemy reaches a particular side of the screen, you lose or lose a life. You may wish to convert your squares to pygame.Rect so you can use pygame.Rect.colliderect(other_rect).

Final Code

# Lists in pygame

import pygame
from pygame.constants import MOUSEBUTTONDOWN
from pygame.locals import K_ESCAPE, KEYDOWN, QUIT

pygame.init()

WIDTH = 640
HEIGHT = 480
SIZE = (WIDTH, HEIGHT)

screen = pygame.display.set_mode(SIZE)
clock = pygame.time.Clock()

# ---------------------------
# Initialize global variables

# position [int, int] -> [x, y]

squares = [
    [50, 50],
    [200, 300],
    [500, 400],
    [200, 50],
    [500, 100]
]

# ---------------------------

running = True
while running:
    # EVENT HANDLING
    for event in pygame.event.get():
        if event.type == KEYDOWN:
            if event.key == K_ESCAPE:
                running = False
        elif event.type == QUIT:
            running = False
        elif event.type == MOUSEBUTTONDOWN:
            mouse_x = event.pos[0]
            mouse_y = event.pos[1]
            print(mouse_x, mouse_y)

            new_square = [mouse_x, mouse_y]
            squares.append(new_square)

    # GAME STATE UPDATES


    # DRAWING
    screen.fill((255, 255, 255))  # always the first drawing command

    for square in squares:
        x = square[0]
        y = square[1]
        pygame.draw.rect(screen, (200, 0, 0), (x, y, 30, 30))

    # Must be the last two lines
    # of the game loop
    pygame.display.flip()
    clock.tick(30)
    #---------------------------


pygame.quit()