Pygame - Maze collisions problem

Question

I am a beginner in Python and Pygame and I have a problem with my game in pygame. I have Maze class and Player class but I can't do proper collisions. I reached the moment where I have no idea why my code isn't working.

Here is my code:

class Maze(pygame.sprite.Sprite):
def __init__(self):
    self.W = 25
    self.H = 14
    self.maze = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
                 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,
                 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1,
                 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1,
                 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 1,
                 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1,
                 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,
                 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1,
                 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1,
                 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 1,
                 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1,
                 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1,
                 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1,
                 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ]
def draw(self,screen):
    block_surf = pygame.image.load(os.path.join(img_folder, "new.png")).convert()
    bx = 0
    by = 0
    for i in range(0,self.W*self.H):
        if self.maze[ bx + (by*self.W) ] == 1:
            screen.blit(block_surf,( bx * 40 , by * 40))
        bx = bx + 1
        if bx > self.W-1:
            bx = 0 
            by = by + 1

def collisions(self):
    bx = 0 
    by = 0 
    for i in range(0, self.W * self.H):
        if self.maze[ bx + (by * self.W) ] == 1:

            rect = pygame.Rect(bx * 40, by * 40, 40, 40)

            if rect.colliderect(Player.get_rect):
                pass  # Collision!
                return False

            bx = bx + 1
            if bx > self.W-1:
                bx = 0 
                by = by + 1
class Player(pygame.sprite.Sprite):
    def __init__(self): #sprite for a player
        pygame.sprite.Sprite.__init__(self) #for sprite working
        self.image = pygame.image.load(os.path.join(img_folder, "player.png")).convert() #look of the sprite
        self.image.set_colorkey(white) #to delete black things around rect img
        self.rect = self.image.get_rect() #kind of border around it
        self.rect.centerx = width/2 + 40
        self.rect.bottom = height- 120
        self.speedx = 0
        self.speedy = 0
    def update(self): #moving player
        maze = Maze()
        collisions = maze.collisions
        self.speedx = 0
        self.speedy = 0
        keystate = pygame.key.get_pressed()
        if keystate[pygame.K_LEFT]:
            if collisions == False:
                self.speedx = 0
            else:
                self.speedx = -1
        elif keystate[pygame.K_RIGHT]:
            if self.rect.x > 920:
                self.speedx = 0
            # elif self.rect.y <= 636 and self.rect.y > 580: 
                # self.speedy = 0
            elif self.rect.x == 40 and self.rect.y < 482 and self.rect.y > 401:
                self.speedy = 0
            elif self.rect.x == 40 and self.rect.y < 399 and self.rect.y > 282:
                self.speedy = 0
            elif self.rect.x == 40 and self.rect.y < 279 and self.rect.y > 160:
                self.speedy = 0 
            elif self.rect.x == 40 and self.rect.y < 157 and self.rect.y > 41:
                self.speedy = 0
            else:
                self.speedx = 1
        elif keystate[pygame.K_UP]:
            if self.rect.y < 41:
                self.speedy = 0
            elif self.rect.y == 159 and self.rect.x > 46 and self.rect.x < 160:
                self.speedy = 0
            elif self.rect.y == 281 and self.rect.x > 45 and self.rect.x < 154:
                self.speedy = 0 
            else:
                self.speedy = -1
        elif keystate[pygame.K_DOWN]:
            if self.rect.y > 480:
                self.speedy = 0
            elif self.rect.x > 405 and self.rect.x < 634 and self.rect.y > 440:
                self.speedy = 0
            elif self.rect.y == 280 and self.rect.x > 46 and self.rect.x < 155:
                self.speedy = 0
            else:
                self.speedy = 1
        self.rect.x += self.speedx
        self.rect.y += self.speedy
    def get_rect(self):
        return pygame.Rect(self.rect.x, self.rect.y, 40, 40)

https://pastebin.com/70fkATnB

Can someone explain to me why it isn't working and help to improve it?

I tried many ideas - even writing from hand positions x and y to create collisions. But it's really bad practice to do so I turned to pygame option sprite.colliderect(sprite2)

https://pastebin.com/70fkATnB

I want to receive information why my code isn't working properly and tips for improving it.

Answer 1

I think you are confused between functions/methods themselves, and calling a function/method.

Take the example

def square_num(num):
    return num * num


print(square_num)
print(square_num(5))

This has output

<function square_num at 0x00950858>
25

That is. when we use square_num without any arguments, python returns a reference to the function, but it doesn't evaluate it. When you give it the arguments (or, for a function without arguments, write () after it) then it actually runs the function. As another example:

def say_hello():
    print("Hello world!")

say_hello
say_hello()

will only print "hello world!" once, only the last line actually runs the function.

Do you understand why the line

if rect.colliderect(Player.get_rect)

can't work now? It is because you are trying to collide a rect with a function, which is meaningless.

The second mistake in that line is calling get_rect on the class Player, rather than an instance of that class. Conceptually this is a rather similar distinction as between a function and an execution of that function. There are many many guides online that explain the difference between a class and a class instance (the latter is also called an object).

To cut a long story short, you need to change your functions to

def collisions(self, player_instance):
    ....
    if rect.colliderect(player_instance.get_rect()):
        print("We've had a collision!")
    ...


def update(self): #moving player
    maze = Maze()
    collisions = maze.collisions(self)

Note, I'd also define the maze in the init method of Player rather than recreating it on every update

Answer 2

I think the main problem stems from this

collisions = maze.collisions  

and this

if collisions == False:  

You are setting the value of collisions to be a function, when you are apparently trying to call that function and use the result.

I would recommend to learn some debugging techniques so you can check your programs control flow as well as the state of its variables.