Pygame, mouse events and threads

[jedi200581]

Hi,

I'm trying to retreive mouse event in a python thread using pygame.
It's not working and I don't know why! Here is the code:

<snippet on>

import pygame, sys, os, threading
from pygame.locals import *
from threading import *

class Display(Thread) :
"""Class managing display"""
def __init__(self, xRes = 640, yRes = 480):
Thread.__init__(self)
#initializing display
self._xRes = xRes
self._yRes = yRes
pygame.display.init()
self._window = pygame.display.set_mode((xRes, yRes))
pygame.display.set_caption('Display')
self._screen = pygame.display.get_surface()
pygame.display.flip()

self._log = []
def input(self, event):
if event.type == KEYDOWN:
sys.exit(0)
else:
print event
def run(self):
print "starting event handling thread"
i = 0
while True:
self.input(pygame.event.wait())

disp = Display()
disp.start()

<snippet off>

When I put the content of the run and input functions in the main
thread, it's working, why not in the thread?

 

[Ben Sizer]

When I put the content of the run and input functions in the main
thread, it's working, why not in the thread?

Because event handling needs to be done in the main thread. So does
rendering. This is a limitation of the underlying system.

As a general rule, try to keep all your PyGame functions in the main
thread and push your other processing into background threads, if you
really need them.

 

[jedi200581]

Because event handling needs to be done in the main thread. So does
rendering. This is a limitation of the underlying system.

As a general rule, try to keep all your PyGame functions in the main
thread and push your other processing into background threads, if you
really need them.

Well, that is a limitation... And is it something that will be fixed or
something that is inherent to pygame and not fixable?

 

[Diez B. Roggisch]

Well, that is a limitation... And is it something that will be fixed or
something that is inherent to pygame and not fixable?

I guess it is part of the SDL pygame sits upon. And I fail to see where
that is a limitation. There can't be multiple event loops - only one.
And if it has to be the main thread, do whatever you wanted to do there,
and whatever your main thread was supposed to do is run in a separate
thread.


Diez

 

[Ben Sizer]

Well, that is a limitation... And is it something that will be fixed or
something that is inherent to pygame and not fixable?

It's inherent to SDL (the library underpinning PyGame), because it's
apparently inherent to some of the platforms it runs on. Rendering and
event handling is typically tied closely to the notion of a window and
that in turn may well be coupled tightly to a single process or thread.
As Diez said however, this is not generally a big problem. Most games
are typically single-threaded anyway.