CODEWITHSUNDEEP
pythonpygame
Jeremy Fisher
Jeremy Fisher

Reputation: 2782

Pygame Sprite not updating

I am trying to move a paddle in a game of Pong by using the up and down arrows. I am doing this through an event handling loop. Here is the code for the event handling loop:

    for event in PE.get():
       if event.type == PG.KEYDOWN:
          keystate = PG.key.get_pressed()
          if event.key == PG.K_ESCAPE:
              done = True
          if keystate[PL.K_UP]:
              rightPaddle.update(-10)
          if keystate[PL.K_DOWN]:
              rightPaddle.update(10)
       if event.type == PG.QUIT:
          done = True

The update function is shown below:

   def update(self, move):
       self.toplefty += move

And here is the PaddleSprite Class:

    def __init__(self, x, y):
        PG.sprite.Sprite.__init__(self)
        self.image = PG.Surface([15,100])
        self.topleftx = x
        self.toplefty = y
        self.rect = self.image.get_rect
        self.rect.move_ip(self.topleftx, self.toplefty)

    def draw(self, surface):
        surface.fill(PINK, self.rect)

    def update(self, move):
        self.toplefty += move

Simply put, the update function for the paddle (which is essentially a rectangle) moves the top left corner of the rectangle to a new y position based on how many times the up or down arrow is clicked. Each up or down arrow increments the paddle a distance of 10 in either the positive or negative direction. However, in my program, the paddle is not moving at all when I press up or down. Can anyone tell me why? Furthermore, is it possible to move the paddles while I hold down the up or down key rather than me pressing it multiple times to move it?

Upvotes: 0

Views: 326

Answers (2)

Bartlomiej Lewandowski
Bartlomiej Lewandowski

Reputation: 11170

It looks like you have combined 2 ways of checking for input. They seem to be conflicting. Let us take a look:

for event in PE.get():

this is called a event loop, what pygame does, is stores an input queue of all the events that have happened, and a get(), pops the value from the queue.

The other method is PG.key.get_pressed().

This is a more of a hardware approach, since it returns an array of button states.

To fix this, I recommend removing the get_pressed() call along with the keystate[] checks and replace them with event.key == PG.K_UP.

EDIT:

It seems that your error is setting a variable of self.toplefty, but using a self.rect to draw. You should use self.rect.move_ip to update, so that it moves the actual rect.

Upvotes: 1

Jeremy Fisher
Jeremy Fisher

Reputation: 2782

Here's how I got it to work:

   def update(self, move):
       self.rect.centerx += 0
       self.rect.centery += move

Essentially, the problem had to be with update because the event driven loop recognized I was pressing up or down. So I just got the Rect object of the sprite and moved its center in the vertical axis. Thanks to everyone who commented or answered!

Upvotes: 0

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