CODEWITHSUNDEEP
pythonpython-3.xpygamecollision-detection
Qwerty
Qwerty

Reputation: 1267

Getting the side of the collision: Collision detection

I am attempting to make a platformer game, in which there are no slopes. I am trying to get collision detection down, but I can't find a way in pygame to get which side collided with the other sprite. Can anyone give me a good way to do this, that isn't too bulky, but would also work well in my situation?

Here is my player class:

class Player(pg.sprite.Sprite):
    def __init__(self,game):
        pg.sprite.Sprite.__init__(self)
        self.image = pg.Surface((30, 40))
        self.game = game
        self.image.fill(YELLOW)
        self.rect = self.image.get_rect()
        self.rect.center = (WIDTH / 2, HEIGHT / 2)
        self.pos = vec(WIDTH / 2, HEIGHT / 2)
        self.vel = vec(0, 0)
        self.acc = vec(0, 0)

    def jump(self):
        self.rect.y += 1
        hits = pg.sprite.spritecollide(self, self.game.platforms, False)
        self.rect.y -= 1
        if hits:
            self.vel.y = -15

    def update(self):
        self.acc = vec(0, PLAYER_GRAV)
        keys = pg.key.get_pressed()
        if keys[pg.K_LEFT]:
            self.acc.x = -PLAYER_ACC
        if keys[pg.K_RIGHT]:
            self.acc.x = PLAYER_ACC
        self.acc.x += self.vel.x * PLAYER_FRICTION
        self.vel += self.acc
        self.pos += self.vel + 0.5 * self.acc


        self.rect.midbottom = self.pos

Here is my platform class:

class Platform(pg.sprite.Sprite):
    def __init__(self, x, y ,w, h):
        pg.sprite.Sprite.__init__(self)
        self.image = pg.Surface((w,h))
        self.image.fill(GREEN)
        self.rect = self.image.get_rect()
        self.rect.x = x
        self.rect.y = y
        self.centerx = x+(w/2)
        self.centery = y+(h/2)

And here is how I currently do collisions (which only works on the top of the platform)

hits = pg.sprite.spritecollide(self.player,self.platforms, False)

if hits:
    self.player.pos.y = hits[0].rect.top+1
    self.player.vel.y = 0

EDIT:

I've added this to my player class and I run it every time the player updates, and it works... almost.

def wall_collisions(self):
    self.rect.centerx = self.pos.x
    for wall in pg.sprite.spritecollide(self, self.walls, False):
        if self.vel.x > 0:
            self.rect.right = wall.rect.left
            self.vel.x = 0
        elif self.vel.x < 0:
            self.rect.left = wall.rect.right
            self.vel.x = 0
        self.pos.x = self.rect.centerx

    self.rect.centery = self.pos.y
    for wall in pg.sprite.spritecollide(self, self.walls, False):
        if self.vel.y > 0:
            self.rect.bottom = wall.rect.top
            self.vel.y = 0
        elif self.vel.y < 0:
            self.rect.top = wall.rect.bottom
            self.vel.y = 0
        self.pos.y = self.rect.centery

The collisions on the top of the platformer work, and the collisions on the side ALMOST always work, except for if I press the player against them then jump. If I try to hit the player on the bottom of the platform, it shoots me to either side of the platform. Any help?

Upvotes: 2

Views: 259

Answers (1)

Qwerty
Qwerty

Reputation: 1267

I've found a working solution to this. The following code works very well.

def wall_collisions(self):
    self.rect.centerx = self.pos.x
    for wall in pg.sprite.spritecollide(self, self.walls, False):
        if self.vel.x > 0:
            self.rect.right = wall.rect.left
            self.vel.x = 0
        elif self.vel.x < 0:
            self.rect.left = wall.rect.right
            self.vel.x = 0
        self.pos.x = self.rect.centerx

    self.rect.centery = self.pos.y
    for wall in pg.sprite.spritecollide(self, self.walls, False):
        if self.vel.y > 0:
            self.rect.bottom = wall.rect.top
            self.vel.y = 0
        elif self.vel.y < 0:
            self.rect.top = wall.rect.bottom
            self.vel.y = 0
        self.pos.y = self.rect.centery

Upvotes: 0

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