On Wed, Mar 12, 2008 at 8:06 PM, Kris Schnee <
kschnee@xxxxxxxxxx> wrote:
Just thought I'd offer this function, which might be useful for
characters with following behavior. It finds the angle from one point to
another, in degrees, with 0 being "up" and 90 being "right." It's
therefore useful for deciding whether a target is to a character's right
etc., and it's easily changed if you don't like the scale I used.
------
import math
def AngleToTarget(dx,dy):
"""Returns the angle to a point (dx,xy) in degrees.
0==up/north, 90==right/east, 180==down/south, 270==left/west.
"""
if dx == 0: ## Special case to prevent zero-division
if dy > 0:
return 180
elif dy < 0:
return 0
else:
return None
oa = float(dy)/float(dx)
theta = math.degrees(math.atan(oa)) + 90.0
if dx > 0:
return theta
else:
return 180+theta
return theta
## Demonstrate the function graphically: show angle from a "sun" to your
cursor.
import pygame
pygame.init()
from pygame.locals import *
s = pygame.display.set_mode((500,500))
font = pygame.font.Font(None,36)
done = False
while not done:
for event in pygame.event.get():
if event.type == KEYDOWN:
done = True
x, y = pygame.mouse.get_pos()
dx, dy = x-250, y-250
theta = AngleToTarget(dx,dy)
s.fill((0,0,0))
pygame.draw.circle(s,(255,255,64),(250,250),10)
t = font.render(str(int(theta)),1,(255,255,255))
pygame.draw.line(s,(128,128,128),(250,250),(x,y))
s.blit(t,(0,0))
pygame.display.update()