Pygame collision: spritecollide has no output

Question

I made a game where you can jump with a sprite and obstacles are moving towards the player. I made a sprite mask to dedect the collision, but nothing happens: for checking I made a simple print statement, what works when two sprites collide. I tested out if the player sprite is faulty, but when I made the player sprite to collide with itself, consol printed collision. So maybe there is a problem with obstacle sprite?

import pygame, random,

pygame.init()


W, H = 800,600
HW, HH = W/2,H/2
AREA = W * H

bg = pygame.image.load('Linn.png')
bg = pygame.transform.scale(bg, (800, 600))

DS = pygame.display.set_mode((W,H))
clock = pygame.time.Clock()



class Player(pygame.sprite.Sprite):
    def __init__(self, x, y, py, paat, veerg, rida):
        super(Player,self).__init__()
        '''Mangija huppamine'''
        self.x = x
        self.y = y

        self.jumping = False
        self.platform_y = py
        self.velocity_index = 0

        '''Sprite sheet'''
        self.paat = pygame.image.load('STlaev.png').convert_alpha()#pildi uleslaadimine
        self.paat = pygame.transform.scale(self.paat,(300,200)) #muutmaks pilti vaiksemaks
        self.rect = self.paat.get_rect()

        '''Sprite sheeti piltide jaotamine pikslite jargi'''
        self.veerg = veerg
        self.rida = rida
        self.kokku = veerg * rida

        W = self.veergL = self.rect.width/veerg
        H = self.weegK = self.rect.height/rida
        HW,HH = self.veergKeskel = (W/2,H/2)

        self.veerg = list([(index % veerg * W, int(index/veerg) * H,W,H )for index in range(self.kokku)])
        self.handle = list([ #pildi paigutamise voimalikud positsioonid
            (0, 0), (-HW, 0), (-W, 0),
            (0, -HH), (-HW, -HH), (-W, -HH),
            (0, -W), (-HW, -H), (-W, -H),])

        self.mask = pygame.mask.from_surface(self.paat)

    def do_jumpt(self):
        '''Huppamine: kiirus, korgus, platvorm'''
        global velocity
        if self.jumping:
            self.y += velocity[self.velocity_index]
            self.velocity_index += 1
            if self.velocity_index >= len(velocity) - 1:
                self.velocity_index = len(velocity) - 1
            if self.y > self.platform_y:
                self.y = self.platform_y
                self.jumping = False
                self.velocity_index = 0



    def draw(self, DS,veergindex,x,y,handle=0):
        DS.blit(self.paat,(self.x+self.handle[handle][0], self.y + self.handle[handle][1]),self.veerg[veergindex])


    def do(self):
        '''Funktsioonide kokkupanek'''
        self.do_jumpt()
        p.draw(DS,index%p.kokku,300,300,0)



p = Player(310, 200, 200, 'STlaev.png', 4, 1) #Mangija algkordinaadid, huppe korgus, pilt, sprite valik
velocity = list([(i/ 2.0)-14 for i in range (0,50)])  #Huppe ulatus
index = 3

def keys(player):
    keys = pygame.key.get_pressed()
    if keys[pygame.K_SPACE] or keys[pygame.K_UP] and player.jumping == False:
         player.jumping = True




class Obsticles(pygame.sprite.Sprite):
    '''Game obsticles: **'''
    #img = pygame.image.load(os.path.join('images', 'box.png'))
    def __init__(self, x, y, width, height):
        super(Obsticles,self).__init__()

        self.img = pygame.image.load('box.png').convert()
        self.img = pygame.transform.scale(self.img, (64,64))
        self.rect = self.img.get_rect()

        self.x = x
        self.y = y
        self.width = width
        self.height = height

        self.mask = pygame.mask.from_surface(self.img)

    def draw(self, DS):
        '''Obsticle img blitting and hitbox'''
        DS.blit(self.img, (self.x, self.y))



def redrawWindow():
    '''Obsticle loop'''
    for i in objects:
        i.draw(DS)




pygame.time.set_timer(pygame.USEREVENT+2, random.choice([2000]))
objects = []


'''Sprites'''
sprites = pygame.sprite.Group()

obsticles = Obsticles(832,300,64,64)
p = Player(310, 200, 200, 'STlaev.png', 4, 1)

all_sprites = pygame.sprite.Group(p,obsticles)
ob = pygame.sprite.Group(obsticles)

x=0
while True:

    '''Game loop'''
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            quit()
        if event.type == pygame.USEREVENT+2:
            r = random.randrange(0,2)
            if r == 0:
                objects.append(obsticles)


    '''Obsticle speed and deleting'''
    for i in objects:
        i.x -= 5     #the speed of the obsticle
        if i.x < -64: #deleting obsticle from the window
            objects.pop(objects.index(i))

    '''Background movement'''
    back_x = x % bg.get_rect().width
    DS.blit(bg, (back_x - bg.get_rect().width, 0))
    if back_x < W:
        DS.blit(bg, (back_x, 0))
    x -= 1

    '''Sprites'''
    all_sprites.update()

    collided = pygame.sprite.spritecollide(p,ob,True,pygame.sprite.collide_mask)
    for i in collided:
        print('Collision.')


    '''Funktsioonid'''
    keys(p)
    p.do()
    index+=1

    redrawWindow()

    pygame.display.update()
    clock.tick(60)

pygame.quit()
quit()

Answer 1

You never move the rects of the involved sprites and since the rects are used for the collision detection and the masks don't overlap in the beginning, the sprites will never collide. Print the rects if something is wrong with the collision detection.

You could add an update method to your sprites in which you set the rect.center or .topleft attribute to the self.x, self.y coords.

def update(self):
    self.rect.center = self.x, self.y

Call all_sprites.update() in the main loop to update all sprites in this group.

One important thing that you must not forget is that pygame.mask.from_surface only works with surfaces that have an alpha channel, that means you have to call convert_alpha instead of convert in the Obsticles class.

self.img = pygame.image.load('box.png').convert_alpha()