Python Pygame collision detection between objects

Question

Hi sorry for the many questions but again I know python but am trying to learn pygame. In the game I'm making im trying to make it so when a block/image touches the sprite it goes back to the top of the screen. I have looked at many tutorials but can't seem to figure it our in a way that would work good. Any advice? Heres the code thanks!!!:

import pygame
import sys
from random import randint
import os

x = 250
y = 30

os.environ["SDL_VIDEO_WINDOW_POS"] = "%d,%d" % (x, y)

width = 1024
height = 768

icon1 = pygame.image.load("Firstpygamegame/santa-claus.png")
pygame.display.set_icon(icon1)

screen = pygame.display.set_mode((width, height))
pygame.display.set_caption("Gift Catcher")
background_image = pygame.image.load("Firstpygamegame/wintervillage.png")

sprite1 = pygame.image.load("Firstpygamegame/santabag2.png")
spriterect = sprite1.get_rect()
speed = 2.5
# 442 or 467
spriterect.x = 442
icon2 = pygame.image.load("Firstpygamegame/present1.png")
icon3 = pygame.image.load("Firstpygamegame/present2.png")
icon4 = pygame.image.load("Firstpygamegame/present3.png")
icon5 = pygame.image.load("Firstpygamegame/present4.png")

cubes = [[
    randint(1, 1000),  # X coordinate
    randint(-1500, -350)]  # Y coordinate, -Y is above screen  (top of screen is zero)
    for x in range(2)]  # 20 cubes

cubes1 = [[
    randint(1, 1000),  # X coordinate
    randint(-1500, -150)]  # Y coordinate, -Y is above screen  (top of screen is zero)
    for x in range(2)]  # 20 cubes

cubes2 = [[
    randint(1, 1000),  # X coordinate
    randint(-1500, -550)]  # Y coordinate, -Y is above screen  (top of screen is zero)
    for x in range(2)]  # 20 cubes

cubes3 = [[
    randint(1, 1000),  # X coordinate
    randint(-1500, -450)]  # Y coordinate, -Y is above screen  (top of screen is zero)
    for x in range(2)]  # 20 cubes

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

    keys = pygame.key.get_pressed()
    spriterect.x += (keys[pygame.K_RIGHT] - keys[pygame.K_LEFT]) * speed
    spriterect.y = 600

    screen.blit(background_image, (0, 0))
    screen.blit(sprite1, spriterect)

    for cb in cubes:
        cb[1] += .25  # cube moves down 2 pixels
        screen.blit(icon2, cb)  # draw cube
        if cb[1] > 800:  # if cube passed bottom of screen
            cb[1] = -100  # move to above screen
            cb[0] = randint(1, 1000)

    for cb in cubes1:
        cb[1] += .25  # cube moves down 2 pixels
        screen.blit(icon3, cb)  # draw cube
        if cb[1] > 800:  # if cube passed bottom of screen
            cb[1] = -100  # move to above screen
            cb[0] = randint(1, 1000)  # random X position

    for cb in cubes2:
        cb[1] += .25  # cube moves down 2 pixels
        screen.blit(icon4, cb)  # draw cube
        if cb[1] > 800:  # if cube passed bottom of screen
            cb[1] = -100  # move to above screen
            cb[0] = randint(1, 1000)  # random X position

    for cb in cubes3:
        cb[1] += .25  # cube moves down 2 pixels
        screen.blit(icon5, cb)  # draw cube
        if cb[1] > 800:  # if cube passed bottom of screen
            cb[1] = -100  # move to above screen
            cb[0] = randint(1, 1000)  # random X position

    pygame.display.flip()

pygame has `pygame.Rect()` to keep object position and size - and it has methods to check collisions between two Rect or Rect and point. So you should use Rect with all cubes — furas, Dec 12 '20 at 02:15

Rabbid76 · Accepted Answer · 2020-12-12T09:18:49.040

Use a pygame.Rect object and colliderect() to find a collision between a rectangle and an object.
pygame.Surface.get_rect.get_rect() returns a rectangle with the size of the Surface object, that always starts at (0, 0) since a Surface object has no position. The position of the rectangle can be specified by a keyword argument:

while running:
    # [...]

    for cb in cubes:
        cb[1] += .25  # cube moves down 2 pixels
        screen.blit(icon2, cb)  # draw cube

        icon_rect = icon2.get_rect(topleft = cb)
        if cb[1] > 800 or icon_rect.colliderect(spriterect):  
            cb[1] = -100  # move to above screen
            cb[0] = randint(1, 1000)

    # [...]

However, you can simplify your code:

icon_list = [icon2, icon3, icon4, icon5]

cube_lists = [[[
    randrange(screen.get_width() - icon.get_width()),
    randint(-1500, -350)] 
    for x in range(2)]
    for icon in icon_list]

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

    keys = pygame.key.get_pressed()
    spriterect.x += (keys[pygame.K_RIGHT] - keys[pygame.K_LEFT]) * speed
    spriterect.y = 600

    screen.blit(background_image, (0, 0))
    screen.blit(sprite1, spriterect)

    for icon, cubes in zip(icon_list, cube_lists):
        for cb in cubes:
            cb[1] += .25  # cube moves down 2 pixels
            screen.blit(icon, cb)  # draw cube

            icon_rect = icon.get_rect(topleft = cb)
            if cb[1] > screen.get_height() or icon_rect.colliderect(spriterect):  
                cb[:] = randrange(screen.get_width() - icon.get_width()), -800

    pygame.display.flip()

pygame.quit()
sys.exit()

Please note, the application loop terminates if running is False. There is no point in setting running = False and to call pygame.quit() and sys.exit() in the event loop. Let the loop run to the end and call pygame.quit() and sys.exit() after the event loop.

Python Pygame collision detection between objects

1 Answers1