Re: [pygame] pygame.key.get_pressed() works unpredictably

["mspaintmaestro@xxxxxxxxx" <mspaintmaestro@xxxxxxxxx>]

I'm curious, can you explain why they shouldn't be used at the same time? Is the adverse reaction between the two a bug? My assumption is that pygame.event.get() and pygame.event.pump() are the only ways to flush the event queue and so must be used at all times (where the latter has more or less identical implementation of the former). If this is the case, then it isn't clear to me when pygame.key.get_pressed() can be used at all. 

On Thu, Apr 5, 2018 at 3:37 PM, René Dudfield <renesd@xxxxxxxxx> wrote:

Hello,

pygame.key.get_pressed() shouldn't be used at the same time as pygame.event.get().

Just use pygame.event.get() instead.

cheers,

On Fri, Apr 6, 2018 at 3:03 AM, gmail aprekates <aprekates@xxxxxxxxx> wrote:

Greeting to all from Greece.

Trying to learn pygame i started with a simple
rect moving with keys that i've read in :
https://nerdparadise.com/programming/pygame/part1

The problem i get with the following code is that 
the rect moves as if i pressed a key more than one 
times. 


import pygame

pygame.init()
screen = pygame.display.set_mode((400, 300))
done = False
is_blue = True
x = 30
y = 30
n = 1
pygame.key.set_repeat()
while not done:
        for event in pygame.event.get():
                if event.type == pygame.QUIT:
                        done = True
                if event.type == pygame.KEYDOWN and event.key == pygame.K_SPACE:
                        is_blue = not is_blue
        pressed = pygame.key.get_pressed()
        if pressed[pygame.K_UP]: y -= 3
        if pressed[pygame.K_DOWN]: y += 3
        if pressed[pygame.K_LEFT]: x -= 3
        if pressed[pygame.K_RIGHT]: x += 3

        screen.fill((0, 0, 0))
        
        if is_blue: color = (0, 128, 255)
        else: color = (255, 100, 0)
        pygame.draw.rect(screen, color, pygame.Rect(x, y, 60, 60))
        
        pygame.display.flip()

after a lot of testing i think pygame.key.get_pressed() works like that. it read kbd's state but that state has inertia! i mean it will keep its values for some time so if you  call key.get.pressed() too soon you'll get again the same state . i tried to simulate same behavior in SDL2 but no lack. but if i looked correctly pygames's src it relies on    SDL1. i dont know if that's related.  

So i'd like some feedback. I could correct the program with controling the frame rate with pygame.clock.

But i'd like to understand why in a basic tutorial a function like key.get_pressed with
plain semantics works so unpredictable.
Ref pages say:

(

pygame.key.get_pressed()

get the state of all keyboard buttons

get_pressed() -> bools

Returns a sequence of boolean values representing the state of every key on the keyboard. Use the key constant values to index the array. A True value means the that button is pressed.

)
But is vague how that 'state' is created , accessed and how it's changed. It 'feels' low level
stuff that involves how keyboard driver works .

Thanks.

chomwitt