I tried changing the default "fill-in" surface size from 1x1 to 200x200 and
removing all the empty 1x1 images in data/characters/noghost, but it had no
effect on speed. This error occurred, however, and it seems to be a result of
removing the 1x1 images (which caused dynamically generated replacements to be
created):
Traceback (most recent call last):
File "hand2hand.py", line 1920, in <module>
main()
File "hand2hand.py", line 1916, in main
game.start_game()
File "hand2hand.py", line 511, in start_game
self.all.update(time_passed)
File "/usr/lib/python2.7/site-packages/pygame/sprite.py", line 399, in update
for s in self.sprites(): s.update(*args)
File "hand2hand.py", line 1789, in update
self.draw_rightarm()
File "hand2hand.py", line 1809, in draw_rightarm
img_a = pygame.surfarray.pixels_alpha(img)
File "/usr/lib/python2.7/site-packages/pygame/surfarray.py", line 208, in
pixels_alpha
return numpysf.pixels_alpha (surface)
File "/usr/lib/python2.7/site-packages/pygame/_numpysurfarray.py", line 302,
in pixels_alpha
offset=start, strides=(4, surface.get_pitch ()))
ValueError: strides is incompatible with shape of requested array and size of
buffer
At any rate, I used cProfiler and copied the results to a text file. It looks
like the draw_rightarm, draw_leftarm, and draw_body methods are the main cause
for the slowdown in the update methods. Using some instances of print(), I have
isolated the slowdown of these methods to the following piece of code, which
occurs in all three:
# Adjust transparency
for row in xrange(0, len(img_a)):
for j in xrange(0, len(img_a[row])):
img_a[row][j] = int(img_a[row][j] * alpha_percent)
img_a is a pygame.surfarray.pixels_alpha object. Based on what I found in the
documentation, this seemed like the most efficient and easy way to make an
image
with per-pixel alpha transparency partially transparent everywhere. But besides
this slowdown problem that I'm having here, pixels_alpha seems to be causing
other problems, as can be seen above. Is there a better way to do what I'm
trying to do in that section of code? I was trying to create a motion trail
effect.
________________________________
From: Ian Mallett <[email protected]>
To: [email protected]
Sent: Tue, April 12, 2011 7:53:24 PM
Subject: Re: [pygame] Whoa! Bad slowdown!
Well, for one thing, on my machine, it segfaults constantly.
I tracked it down to ~line 1006:
scaled = pygame.transform.smoothscale(img, size)
But there doesn't seem to be anything out of the ordinary there. Maybe trying
to resize many 1x1 surfaces to 400x400 leads to a memory leak somewhere in
PyGame?
Ian
