On Wed, Nov 04, 2009 at 05:23:42PM +0000, Kris Schnee wrote:
> On Wed, 4 Nov 2009 09:21:58 -0800, James Paige <b...@hamsterrepublic.com>
> wrote:
> > A quick test with the timeit module suggest that the ** operator is not
> > slower.
>
> > Here is how I would write the distance check:
> >
> > def is_in_range(enemy, tower):
> > return (enemy.x-tower.x)**2 + (enemy.y-tower.y)**2 <= tower.range**2
>
> If speed is important, how about trying a cruder orthogonal method?
>
> def IsInRange(enemy,tower):
> return (enemy.x-tower.x) + (enemy.y-tower.y) <= tower.range
Did you mean?:
def IsInRange(enemy,tower):
return abs(enemy.x-tower.x) + abs(enemy.y-tower.y) <= tower.range
That gives you a diamond-shaped range instead of a round range, which
would be fine for some games, but maybe not a tower defence game.
I was curious how much faster it would be, so I ran some tests:
ja...@rhinoctopus:~/tmp$ ./timeit.py -n 10000000 'import range1'
15 10
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. . . . . . . . . . . . . . . # . . . . . . . . . . . . . .
. . . . . . . . . . . . # # # # # # # . . . . . . . . . . .
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. . . . . . . . . # # # # # # # # # # # # # . . . . . . . .
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. . . . . . . . # # # # # # # # # # # # # # # . . . . . . .
. . . . . . . . # # # # # # # # # # # # # # # . . . . . . .
. . . . . . . # # # # # # # # X # # # # # # # # . . . . . .
. . . . . . . . # # # # # # # # # # # # # # # . . . . . . .
. . . . . . . . # # # # # # # # # # # # # # # . . . . . . .
. . . . . . . . # # # # # # # # # # # # # # # . . . . . . .
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10000000 loops, best of 3: 0.976 usec per loop
ja...@rhinoctopus:~/tmp$ ./timeit.py -n 10000000 'import range2'
15 10
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. . . . . . . . . . . . . . # # # . . . . . . . . . . . . .
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. . . . . . . . . # # # # # # # # # # # # # . . . . . . . .
. . . . . . . . # # # # # # # # # # # # # # # . . . . . . .
. . . . . . . # # # # # # # # X # # # # # # # # . . . . . .
. . . . . . . . # # # # # # # # # # # # # # # . . . . . . .
. . . . . . . . . # # # # # # # # # # # # # . . . . . . . .
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. . . . . . . . . . . . . # # # # # . . . . . . . . . . . .
. . . . . . . . . . . . . . # # # . . . . . . . . . . . . .
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10000000 loops, best of 3: 0.969 usec per loop
So I think the difference is too small to be worth it.
range1 and range2 are just two copies of this script, with one of the
tests commented out at the end:
#!/usr/bin/env python
width = 30
height = 20
center_x = int(width / 2)
center_y = int(height / 2)
radius = 8
print center_x, center_y
def in_range(x1, y1, x2, y2, r):
return (x1 - x2)**2 + (y1 - y2)**2 <= r**2
def in_ortho_range(x1, y1, x2, y2, r):
return abs(x1 - x2) + abs(y1 - y2) <= r
def draw_field(dist_func):
for y in xrange(height):
for x in xrange(width):
if x == center_x and y == center_y:
print "X",
elif dist_func(x, y, center_x, center_y, radius):
print "#",
else:
print ".",
print ""
draw_field(in_range)
draw_field(in_ortho_range)
