Python calling method from super class via child class not working as expected

Question

I have extended pygame.Rect with my Ball class. When I use nstanceOfBall.colliderect() (line 66), no errors are thrown, yet it never returns true. Any insight into why colliderect isn't working for my Ball instances?

    import sys, pygame
    import os
    import ball
    import random
    import math
    #from ball import Ball

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

    class Ball(pygame.Rect):
        def __init__(self, x, y, width, height, screenWidth, screenHeight):
            super(pygame.Rect,self).__init__(x, y, width, height)
            self.floatX=x
            self.floatY=x
            self.screenWidth=screenWidth
            self.screenHeight=screenHeight
            self.speed=[random.random()*5-2.5, random.random()*5-2.5]

        def runLogic(self):
            self.floatX+=self.speed[0]
            self.floatY+=self.speed[1]

            if self.floatX+16<0: self.floatX=self.screenWidth
            if self.floatX>self.screenWidth: self.floatX=-16
            if self.floatY+16<0: self.floatY=self.screenHeight
            if self.floatY>self.screenHeight: self.floatY=-16

            self.x=self.floatX
            self.y=self.floatY

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

    os.environ['SDL_VIDEO_WINDOW_POS'] = "%d,%d" % (700, 200)#1680,1440)

    pygame.init()

    size = width, height = 320, 240
    white = 255, 255, 255
    blue=0,0,255

    screen = pygame.display.set_mode(size)

    image = pygame.image.load("ball.png")
    ballRect=image.get_rect()
    balls = []

    for x in range(0, 100):
        balls.append(Ball(random.random()*width, random.random()*height, ballRect.width, ballRect.height, width, height))

    lastFrameStartTime=pygame.time.get_ticks()

    while 1:
        for event in pygame.event.get():
            if event.type == pygame.QUIT: 
                sys.exit()

            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_ESCAPE:
                    sys.exit()

        for ball in balls:
            ball.runLogic()

            for ball2 in balls:
                if ball != ball2:                
                    if ball.colliderect(ball2):
                        print("collision detected!")
                        balls.pop(balls.index(ball))
                        balls.pop(balls.index(ball2))
                        #balls.remove(ball2)

        screen.fill(blue)
        for ball in balls:
            screen.blit(image, ball)
        pygame.display.flip()

        pygame.time.wait(33-(pygame.time.get_ticks()-lastFrameStartTime))
        lastFrameStartTime=pygame.time.get_ticks()

Using super(Ball, self) instead of super(pygame.Rect, self) in Ball.init did the trick.

Thank you.

Answer 1

The first arument to super must be the current class, i.e. Ball instead of pygame.Rect:

class Ball(pygame.Rect):
    def __init__(self, x, y, width, height, screenWidth, screenHeight):
        super(Ball, self).__init__(x, y, width, height)
        ...

There is an example in the documentation on super.

The point of super is that it allows you to call the next method in the inheritance order without requiring you to refer to the parent class explicitly. This comes handy when using multiple inheritance, see e.g. super confusing python multiple inheritance super()