I am having trouble coding my collision check function for my fps game. How can I write my collision function?

Question

I am stuck on how to write my collision function in my player class. Also should I put my collision check function in my player class or should it be in my bullet class? I honestly don't know. I mean common sense says my bullet should have the collision check function in it, just because I want the top of my bullet checking if it hits a falling cement block sprite, but I don't know.... I would appreciate an answer on how to code my collision function. This would really help me out. My collision function is right below my shoot function in my player class.

My code:

import pygame

pygame.init()

#screen settings
WIDTH = 1000
HEIGHT = 400

screen = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption("AutoPilot")
screen.fill((255, 255, 255))

#fps
FPS = 120
clock = pygame.time.Clock()

#load images
bg = pygame.image.load('background/street.png').convert_alpha() # background
bullets = pygame.image.load('car/bullet.png').convert_alpha()
debris_img = pygame.image.load('debris/cement.png')

#define game variables
shoot = False

#player class
class Player(pygame.sprite.Sprite):
    def __init__(self, scale, speed):
        pygame.sprite.Sprite.__init__(self)

        self.bullet = pygame.image.load('car/bullet.png').convert_alpha()
        self.bullet_list = []
        self.speed = speed
        #self.x = x
        #self.y = y
        self.moving = True
        self.frame = 0
        self.flip = False
        self.direction = 0

        #load car
        self.images = []
        img = pygame.image.load('car/car.png').convert_alpha()
        img = pygame.transform.scale(img, (int(img.get_width()) * scale, (int(img.get_height()) * scale)))
        self.images.append(img)
        self.image = self.images[0]
        self.rect = self.image.get_rect()
        self.update_time = pygame.time.get_ticks()
        self.movingLeft = False
        self.movingRight = False
        self.rect.x = 465
        self.rect.y = 325

    #draw car to screen
    def draw(self):
        screen.blit(self.image, (self.rect.centerx, self.rect.centery))

    #move car
    def move(self):
        #reset the movement variables
        dx = 0
        dy = 0

        #moving variables
        if self.movingLeft and self.rect.x > 33:
            dx -= self.speed
            self.flip = True
            self.direction = -1
        if self.movingRight and self.rect.x < 900:
            dx += self.speed
            self.flip = False
            self.direction = 1

        #update rectangle position
        self.rect.x += dx
        self.rect.y += dy

    #shoot
    def shoot(self):
        bullet = Bullet(self.rect.centerx + 18, self.rect.y + 30, self.direction)
        bullet_group.add(bullet)

    #def collision(self):
        #write code here




#bullet class
class Bullet(pygame.sprite.Sprite):
    def __init__(self, x, y, direction):
        pygame.sprite.Sprite.__init__(self)

        self.speed = 5
        self.image = bullets
        self.rect = self.image.get_rect()
        self.rect.center = (x,y)
        self.direction = direction

    def update(self):
        self.rect.centery -= self.speed
        #check if bullet has gone off screen
        if self.rect.top < 1:
            self.kill()

#debris class
class Debris(pygame.sprite.Sprite):
    def __init__(self, x, y, scale, speed):
        pygame.sprite.Sprite.__init__(self)

        self.scale = scale
        self.x = x
        self.y = y
        self.speed = speed
        self.vy = 0
        self.on_ground = True
        self.move = True
        self.health = 4
        self.max_health = self.health
        self.alive = True

        #load debris
        self.image = debris_img
        self.rect = self.image.get_rect()
        self.rect.center = (x,y)

######################CAR/DEBRIS##########################

player = Player(1,5)
debris = Debris(300,15,1,5)

##########################################################

#groups
bullet_group = pygame.sprite.Group()
debris_group = pygame.sprite.Group()

debris_group.add(debris)

#game runs here
run = True
while run:

    #draw street
    screen.blit(bg, [0, 0])

    #update groups
    bullet_group.update()
    bullet_group.draw(screen)

    debris_group.update()
    debris_group.draw(screen)

    #draw car
    player.draw()
    player.move()

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False

        #check if key is down
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_ESCAPE:
                run = False
            if event.key == pygame.K_a:
                player.movingLeft = True
            if event.key == pygame.K_d:
                player.movingRight = True
            if event.key == pygame.K_SPACE:
                player.shoot()
                shoot = True

        #check if key is up
        if event.type == pygame.KEYUP:
            if event.key == pygame.K_a:
                player.movingLeft = False
            if event.key == pygame.K_d:
                player.movingRight = False

    #update the display
    pygame.display.update()
    pygame.display.flip()
    clock.tick(FPS)

pygame.quit()

Answer 1

I suggest reading How do I detect collision in pygame?. Use pygame.sprite.spritecollide() for the collision detection. Set the dokill argument True. So the bullets gat automatically destroyed.

The following code is base on one of your previous questions: Check collision of bullet sprite hitting cement block sprite

class Car(pygame.sprite.Sprite):
    # [...]

    def collision(self, debris_group):
        for debris in debris_group:
            if pygame.sprite.spritecollide(debris, bullet_group, True):
                debris.health -= 1
                if debris.health <= 0:
                    debris.kill()