Hi,
On Tue, Jan 16, 2018 at 10:37 AM, dejohnso <dejoh...@cs.utah.edu> wrote:
> I have having trouble with a basic game/animation loop.
>
> It seems like the final frame doesn't show up until after the game loop is
> done and pygame.quit() is called. An example is below - if it is run, I see
> the "Out of loop" output, then a pause, then the final frame, then the
> final pause.
>
Great self-contained example!
On Win 7 x86-64, Python 3.5.1, PyGame 1.9.2a0, I see 5 frames of animation,
with the last frame being presented an instant before "Out of loop" is
printed. This is the behavior I would expect, but it sounds like your last
frame comes 1s after printing?
> Am I doing something wrong?
Everything here looks good to me. I would prefer the drawing code
(including display update) all in one place (idiomatically, at the end of
the frame). I also prefer `pygame.display.flip()`. Also, in this case,
`time.sleep(...)` instead of `.tick(...)` (due to the low framerate, see
below). But these are all suggestions; nothing as-is looks wrong.
> Is this specific to my setup/machine?
>
Since I can't reproduce it myself, this seems likely. What is your
setup/machine?
I have a few vague suspicions. If the input polling rate is very low, some
windowing systems will conclude the process is hung, and possibly draw some
kind of grayed-out overlay on the window, which can make it drop a frame or
two. Also, `.tick(...)` does some internal timekeeping history
measurements, meaning that the framerate provided is rather inaccurate,
especially on startup. That's why I'd prefer `time.sleep(...)` (OTOH, *slow*ing
the framerate should work just fine, so . . .).
> import pygame, sys
>
> def main():
> pygame.init()
> screen = pygame.display.set_mode((600, 400))
>
> frame_count = 0
>
> # The clock helps us manage the frames per second of the animation
> clock = pygame.time.Clock()
>
> square = pygame.Rect((0,100),(50,50))
> done = False
> while not done:
> # Erase the screen
> screen.fill((50, 50, 50))
> # Process events
> for event in pygame.event.get():
> if event.type == pygame.QUIT:
> done = True
> # The main snake code
> square.move_ip((50,0))
> pygame.draw.rect(screen, (200,50,50), square)
> print(square)
> frame_count += 1
> if frame_count >= 5:
> done = True
> print(done)
> # set fps
> clock.tick(1)
> # Bring drawn changes to the front
> pygame.display.update()
>
> print("Out of loop")
> pygame.time.delay(2000)
> # This also works to bring up the last frame.
> # pygame.event.clear()
> # pygame.event.wait()
> pygame.quit()
> print("After quit")
> pygame.time.delay(2000)
> sys.exit()
>
> main()
>
>
(Waves from SoC)
Ian
