For loop in my collide function never hitting?

Question

I'm trying to make a tile based game in pygame and I can't quite get my collision function work. So far I have it that when I hit WASD it checks if it is a valid move before actually moving the sprite.

    def move(self, dx=0, dy=0):
        print("TEST" + str(self.collide_with_walls(dx, dy)))
        if not self.collide_with_walls(dx, dy):
            self.x += dx
            self.y += dy

This is my move function that calls my collide function (Figured I would include it just in case)

def collide_with_walls(self, dx=0, dy=0):
        print("Here 1")
        print(self.game.walls)
        for wall in self.game.walls:
            print("2")
            if wall.x == self.x + dx and wall.y == self.y + dy:
                print("Hit wall")
                return True
            print("No hit wall")
        return False

This is my collide function that is constantly returning false. Important to note that it is never printing "2" so it is never getting in the for loop and when I print out 'self.game.walls' it prints "<Group(0 sprites)>

class Wall(pg.sprite.Sprite):
    def __init__(self, game, x, y):
        self.groups = game.all_sprites, game.walls
        pg.sprite.Sprite.__init__(self, self.groups)
        self.game = game
        self.image = pg.Surface((TILESIZE, TILESIZE))
        self.image.fill(BLACK)
        self.rect = self.image.get_rect()
        self.x = x
        self.y = y
        self.rect.x = x * TILESIZE
        self.rect.y = y * TILESIZE

And here lies the Wall function that places the wall where I have a hunch that the problem is but I can't seem to figure it out. Any advice helps :)

Just a test to see what is stored in there considering how it was getting to the collision function but never into the for loop — Gavin Tynan, Aug 21 '20 at 22:13
What class of object is self.game.walls supposed to be? A list-like of Walls? — Eric Canton, Aug 21 '20 at 22:15
It prints . I wrote most of this a year ago so not entirely sure but I've been under the impression it was a list. EDIT: When I printed out the type of it I got — Gavin Tynan, Aug 21 '20 at 22:22
Might `` indicate that there are no sprites (i.e. walls) in the group? So you never enter the for loop. — rcriii, Aug 21 '20 at 23:14

Rabbid76 · Answer 1 · 2020-10-16T05:49:09.247

0

I recommend to use pygame.Rect() a and collidepoint() or colliderect for the collision test. For instance:

def collide_with_walls(self, dx=0, dy=0):
        
        new_rect = self.image.get_rect(topleft = (self.x + dx, self.y + dy))
        
        for wall in self.game.walls:
           
            if new_rect.colliderect(wall.rect):  
                print("Hit wall")
                return True
           
        return False

edited Oct 16 '20 at 05:49

answered Aug 22 '20 at 05:16

Rabbid76

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The problem is in my self.game.walls, I can't get to the collision detection part because the for loop never runs. – Gavin Tynan Aug 22 '20 at 22:12
@GavinTynan So if the walls are not in `self.game.walls`, where are they? – Rabbid76 Aug 23 '20 at 07:27
Who knows ¯\_(ツ)_/¯ – Gavin Tynan Aug 25 '20 at 18:46

For loop in my collide function never hitting?

1 Answers1