Re: [pygame] Problems with keys

[James Paige <Bob@xxxxxxxxxxxxxxxxxxx>]

On Thu, Apr 06, 2006 at 07:00:05PM +0300, Juha wrote:
>    Hi,
>     
>    I'm not sure if this was already posted, sorry for double posting if it
>    was. I tried to send this mail before adding myself to the mailing list.
>     
>    I have a simple program that displays an image and moves it to the left or
>    right based on which arrow key the user pressed. Here's the code:
>     
>    [*clip!*]
>     
>    The problem is that if the user holds one of the buttons, quickly releases
>    it, and then starts pressing the other, the image stops moving. It's
>    like the program starts ignoring the key repeats or something. I'd like to
>    have the image just change direction without the user having to stop
>    pressing the key and then again pressing it to get the image moving. The
>    image moves correctly if the user changes keys a bit slower, but is there
>    a way to make the program respond faster? I've tried checking the keys
>    with both key.get_pressed() as well as event.type == KEYDOWN, but both
>    have the same problem.
>     
>    Juha Salo

You don't really want to be using key repeats at all. keyboard repeats 
will never be all that reliable for game-input purposes. Instead, you 
want to catch both KEYDOWN and KEYUP events. Here is an example:

import os
import pygame
from pygame.locals import*

pygame.init()

screen = pygame.display.set_mode((800,600))
pygame.display.set_caption("test")
pygame.mouse.set_visible(1)
bg = pygame.Surface(screen.get_size())
bg.convert()
bg.fill((0,0,0))
screen.blit(bg, (0,0))
pygame.display.flip()

t = pygame.image.load(os.path.join("..","content","timmy.tga"))
tr = t.get_rect()
tr.topleft = (0,0)

goLeft = False
goRight = False

run = True
while run:
   screen.blit(bg, (0,0))
   for event in pygame.event.get():
       if event.type == QUIT:
           run = False
           break

       if event.type == KEYDOWN:
           if event.key == K_LEFT:
               goLeft = True
           elif event.key == K_RIGHT:
               goRight = True

       if event.type == KEYUP:
           if event.key == K_LEFT:
               goLeft = False
           if event.key == K_RIGHT:
               goRight = False

   if goLeft and not goRight:
        tr = tr.move(-5,0) 
   if goRight and not goLeft:
        tr = tr.move(5,0)

   screen.blit(t, tr)
   pygame.display.flip()



Now eventually you will probably want to wrap the goRight and goLeft 
into members of a game character class, or have a "velocity" member, or 
something more object-oriented than this example, but as far as the 
keyboard handling goes, I think this is what you want.

(and don't forget to use os.path.join() for your directory names!)

---
James Paige