Okay...
First of all, I don't know anything beyond some vague stab at calculating
framerates. Honestly, I haven't gone beyond using pygame.time.wait(),
because it did what it was supposed to do. The way I started to measure
things in terms of some sort of framerate was just Pixels Per Tick. Even
then, I really don't think I know what I'm talking about in terms of timing
:D
The event manager you see in the code is more or less ripped from the MVC
tutorial from the link posted a few mails back. I'm not entirely certain why
it's there, but I assume it may be to do with something further along in the
original author's tutorial (where he starts jamming in network code). You'll
also notice another "useless" variable in the CpuController called
self.newevent. It's safe to say you can probably take both of these
variables out and it'll still run fine.
The one difference between the pong code and the code in the original
tutorial is that in my code, there are technically two TickEvents going on.
The first one regulates the state of the game, updating display, etc, and
then there's PongTickEvent, which was created specifically to control the
motion of the ball, so I could toggle a variable to pause the game. If I had
toggled the TickEvent to an "off" state, I would no long have any control
over input. In a very tenuous way, this acted like a thread. I do stress the
tenuous part.
In terms of *real* threading, I'm not sure how Python handles threading
(I've only been using python for a couple of weeks), but I think if it's
anything like I'm used to, you could launch each controller in a separate
thread, and bottleneck them through the event manager. Although I'm sure
this could lead to situations where some threads may become starved, and a
trivial per-tick action gains priority over something massively important,
such as redrawing the screen. Pygame is good enough as it is (as far as I
can see) that it doesn't really required threading. I'm working on an
isometric game with a world built out of roughly 2500 sprites, which are all
actively listening to see if the mouse is over it, couple that with (at last
count) 100 larger sprites roaming the "surface" of the world and two
parallax scrolling background images. I was initially concerned that I was
going to get a lot of slowdown, and thought threading was the answer,
however, it turned out that I just had to use a flag on my surfaces to speed
them up. I never once saw the manager get choked up with events, and since
all events had to go through it to perform their duty, everything ran at
exactly the same speed.
So yes, threading is a very definite idiom you could apply, but I would
explore all possible avenues of operation before heading down to threading
town :)
Lastly, I think I know what you mean. You're worried that an event,
regardless of its final destination, is going to pass through each
controller until it hits the right spot (if it has one). The events
themselves are already in a weakref dictionary, so I *think* that answers
part of your question... If you're concerned about efficiency, remember that
you're already saving a whole bunch of CPU cycles from just moving off the
basic while true loop. However, I'm kind of interested now to see the
lifetime of an event, so I'll modify my code a little here to see if the
event really does hit each listener in turn before getting to where it needs
to go.
Sorry for waffling.
-----Original Message-----
From: owner-pygame-users@xxxxxxxx [mailto:owner-pygame-users@xxxxxxxx]On
Behalf Of DR0ID
Sent: Wednesday, April 26, 2006 14:54
To: pygame-users@xxxxxxxx
Subject: Re: [pygame] Training Pong MVC
Hi
Thanks for your tutorial. I'm fascinated by the MVC model, because it
seems tu run very fast. I wonder, what framerates this game has but dont
know how to messure it. I tried following:
class RedrawController:
def __init__(self, eventManager):
self.eventManager = eventManager
self.eventManager.RegisterListener(self)
self._clock = pygame.time.Clock()
def Notify(self, event):
"""
Redraw all updated surfaces
"""
if isinstance(event, RedrawEvent):
game.pong_static_group.draw(game.screen)
dirty_rects = game.pong_dynamic_group.draw(game.screen)
pygame.display.update(dirty_rects)
self._clock.tick()
pygame.display.set_caption(str(self._clock.get_fps()))
and in the CpuController.Run() I commentet out the two lines after the
while keyword.
I do not know if this is the correct framerate. (putting the clock into
the CPUController.Run() is not the right place because not all deliverd
events are RedrawEvents).
Some questions:
In the EventManager there ist a self.eventQueue = [] which is not used
and gave me the idea and question:
Is it easy to run a controller or any other component in a different
thread that stuffs the eventmanager's eventqueue? (should be threadsafe
+ EventManager has to change a bit for that) (ok running every component
in a different thread should be possible or is it not?)
In your EventManager all registered listners get all events, also if
they do not use them all. Would it not be a bit slow if there are many
objects and many events to dispatch? Would it be better to only notify a
object if it has registered for the event type to dispatch? (ok then you
have to check befor dispatching and makes things a bit more complicatet
perhaps using a dict like {eventtype:[listners], ....} (also a weakref
list?) )
In a complexer application there can be many more different events, right?
~DR0ID
Chris Ashurst schrieb:
Just to confirm: Yes, that's the tutorial.
It's a little confusing if you follow his example, but as long as you walk
away with the concept of having an event manager that listens for events
sent by controllers, you will also walk away with the fact that you won't
have to use the usual "while 1:" method of looping.
In fact, I would like to share my MVC Pong program, as I think it's been
simplified and commented enough to explain what's going on. It's at
http://telestatic.net/python/pong.py
I'm not claiming that it's the ultimate superior last-word in pygame
programming, or even of the MVC model, but it gets the message across :)
~Chris
-----Original Message-----
From: owner-pygame-users@xxxxxxxx [mailto:owner-pygame-users@xxxxxxxx]On
Behalf Of Laura Creighton
Sent: Tuesday, April 25, 2006 00:53
To: pygame-users@xxxxxxxx
Cc: lac@xxxxxxxxxx
Subject: Re: [pygame] Training
In a message of Mon, 24 Apr 2006 22:34:06 EDT, "R. Alan Monroe" writes:
As far as my personal extra 0.02 goes, I found the tutorial for using t
he
MVC model with Pygame incredibly useful.
URL?
Alan
I am not the original poster, but I suspect he or she means:
http://sjbrown.ezide.com/games/writing-games.html
Laura
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