How can I have two key_input methods in pygame?

Question

I have found that I can only have one method for key input. Bellow I have two methods (movementsprite, and movementspritevert) I have found that I can only have one work. If I initiate both, the top one runs, and the second one does nothing. Is there a way around this? Am I doing something wrong?

Original Program

----Movement File------

    import pygame
    import os, sys
    from itertools import *
    from oryxsprites import *
    from oryxdisplay import *
    spritex = 320
    spritey = 320

    screen = pygame.display.set_mode((640, 640))
    def movementsprite():   

        global spritex

        keys = pygame.key.get_pressed()

        for event in pygame.event.get():
             if event.type == pygame.QUIT:
                 running = False
             elif event.type == pygame.KEYDOWN:

                 if event.key == pygame.K_RIGHT:
                     if spritex == 576:
                         spritex += 0
                     else:
                         spritex += 32 

                 elif event.key == pygame.K_LEFT:              
                     if spritex == 32:
                         spritex -= 0
                     else:
                         spritex -= 32

        return spritex
    def movementspritevert():   

        global spritey

        keys = pygame.key.get_pressed()

        for event in pygame.event.get():
             if event.type == pygame.QUIT:
                 running = False
             elif event.type == pygame.KEYDOWN:

                 if event.key == pygame.K_DOWN:
                     if spritey == 576:
                         spritey += 0
                     else:
                         spritey += 32 

                 elif event.key == pygame.K_UP:              
                     if spritey == 32:
                         spritey -= 0
                     else:
                         spritey -= 32

        return spritey

-------Main File------]

running = True

while running:

    backgroundmain()
    pygame.display.set_caption('OryxGame')
    #pygame.display.set_icon(grasstile)
    movementsprite()
    movementspritevert()

    pygame.display.flip()


    for event in pygame.event.get():
         if event.type == pygame.QUIT:
             running = False
             pygame.quit()

------Display file----

def backgroundmain():
    spritex = movementsprite()
    spritey = movementspritevert()
    backdrop = pygame.Rect(0, 0, 640, 640) 
    screen.fill((50,50,50))
    playingfeildwidth = (32, 608)
    playingfeildheight = (32, 608)

    screen.blit(warrior1, (spritex, spritey))

------Possible solution -------------

-Main File----

 while running:

    backgroundmain()
    pygame.display.set_caption('OryxGame')
    #pygame.display.set_icon(grasstile)
    movementsprite(events)
    movementspritevert(events)

    pygame.display.flip()


    for event in pygame.event.get():
         if event.type == pygame.QUIT:
             running = False
             pygame.quit()

-----Display File-----

def backgroundmain():
    events = pygame.event.get()
    spritex = movementsprite(events)
    spritey = movementspritevert(events)
    backdrop = pygame.Rect(0, 0, 640, 640) 
    screen.fill((50,50,50))
    playingfeildwidth = (32, 608)
    playingfeildheight = (32, 608)

------Key Input File-----------

spritex = 320
spritey = 320
screen = pygame.display.set_mode((640, 640))
def movementsprite(events):  
    global spritex
    keys = pygame.key.get_pressed()

    for event in events:
         if event.type == pygame.QUIT:
             running = False
         elif event.type == pygame.KEYDOWN:

             if event.key == pygame.K_RIGHT:
                 if spritex == 576:
                     spritex += 0
                 else:
                     spritex += 32 

             elif event.key == pygame.K_LEFT:              
                 if spritex == 32:
                     spritex -= 0
                 else:
                     spritex -= 32

    return spritex
def movementspritevert(events):   
    global spritey
    keys = pygame.key.get_pressed()

    for event in events:
         if event.type == pygame.QUIT:
             running = False
         elif event.type == pygame.KEYDOWN:

             if event.key == pygame.K_DOWN:
                 if spritey == 576:
                     spritey += 0
                 else:
                     spritey += 32 

             elif event.key == pygame.K_UP:              
                 if spritey == 32:
                     spritey -= 0
                 else:
                     spritey -= 32

    return spritey

---Error---

Traceback (most recent call last):
  File "C:\Users\Eric\Dropbox\oryxgame\oryxgame.py", line 12, in <module>
    backgroundmain()
  File "C:\Users\Eric\Dropbox\oryxgame\oryxdisplay.py", line 11, in backgroundmain
    spritey = movementspritevert(events)
TypeError: movementspritevert() takes no arguments (1 given)

----Full Code----

Have you posted all of the code to demonstrate your problem? I don't see where either of these functions is called or referenced. — matt b
– matt b, Commented May 23, 2012 at 0:37
I added the rest of the files/code. I figure the problem would be in the Key-press section so I had only included that. @matt b — enrique2334
– enrique2334, Commented May 23, 2012 at 0:47
Why can't you make use of two globals in movementsprite, and simply handle the various cases there? Also, I note that you are effectively calling those two functions twice - in backgroundmain() you call movementsprite, and then within the same loop you call it again. You need only read the input once per loop. — dwerner
– dwerner, Commented May 23, 2012 at 0:54
I was trying to use both global's in movement sprite but it cause the sprite to move diagonally. @dwerner — enrique2334
– enrique2334, Commented May 23, 2012 at 0:56

machow · Accepted Answer · 2012-05-23 19:40:01Z

3

The problem is that event.get() removes the events from queue (see docs). So, when your second function uses event.get(), there aren't any events remaining in the queue, unless they were able to slip in during the extremely short interval between calls.

To see this problem in action, put a print event after calling for event in pygame.event.get() in the first function, then try it in the second.

One way to fix this would be

    events = pygame.event.get()
    function1(events)
    function2(events)

Then use a for loop over events instead.

EDIT: to clarify how to implement

It's likely your code threw an error because pygame.event.get() was called before initializing pygame. You could use something like,

def backgroundmain():
    events = pygame.event.get()                #save events
    spritex = movementsprite(events)           #added events arg
    spritey = movementspritevert(events)       #added events arg
    backdrop = pygame.Rect(0, 0, 640, 640) 
    screen.fill((50,50,50))
    playingfeildwidth = (32, 608)
    playingfeildheight = (32, 608)

    screen.blit(warrior1, (spritex, spritey))

Then, change the movement functions from this:

def movementspritevert():   

    #Do stuff ...

    for event in pygame.event.get():
         if event.type == pygame.QUIT:
             running = False
         elif event.type == pygame.KEYDOWN:

to this:

def movementspritevert(events):   

    #Do stuff ...

    for event in events:
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.KEYDOWN:

The key is that every time you use event.get(), it will remove the events, so your next call won't get the same events. Basically, if you want one key press to be used by all of your movement functions, then save the events as a variable and pass that to the functions.

edited May 23, 2012 at 19:40

answered May 23, 2012 at 2:03

machow

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13 Comments

enrique2334 Over a year ago

So I tried what you suggested.I added the events = pygame.event.get() to the top, above my funtions. I got an error error: video system not initialized. so I removed the (). I know I am doing this wrong. I added the changed code to the bottom of my question. @Closed

machow Over a year ago

It sounds like you used pygame.event.get() before pygame.init(). I updated my answer with one way you could make the changes.

enrique2334 Over a year ago

So I got the error spritey = movementspritevert(events) then TypeError: movementspritevert() takes no arguments (1 given) Im not exactly sure what this means. Do you? @Closed

hammythepig Over a year ago

I don't think you changed your call to def movementspritevert(events):. Look at what Closed wrote and copy that (just keep in mind he forgot to indent running = False)

machow Over a year ago

Thanks for catching the misindent! Can you search your script for "def movementspritevert():"? Like hammythepig said, it looks like it either didn't get changed (or is defined more than once).

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