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# simu  Robot simulation. {{{
#
# Copyright (C) 2012 Nicolas Schodet
#
# APBTeam:
# Web: http://apbteam.org/
# Email: team AT apbteam DOT org
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place  Suite 330, Boston, MA 021111307, USA.
#
# }}}
"""Obstacle with a polygonal shape."""
from utils.observable import Observable
from simu.utils.vector import vector
from simu.utils.trans_matrix import TransMatrix
from math import pi
import simu.utils.intersect
class PolygonalObstacle (Observable):
def __init__ (self, *points, **kwargs):
Observable.__init__ (self)
self.pos = None
self.angle = 0
self.points = points
self.level = 0
for i in kwargs:
if i == 'level':
self.level = kwargs[i]
else:
raise TypeError ("unexpected keyword argument")
def intersect (self, a, b):
"""If the segment [AB] intersects the obstacle, return distance from a
to intersection point, else, return None."""
if self.pos is None or self.angle is None:
return None
# Find intersection with each segments. Return the nearest.
m = TransMatrix ()
m.translate (self.pos)
m.rotate (self.angle)
p = m.apply (*self.points)
found = None
def iter_seg (p):
for i in xrange (len (p)  1):
yield p[i], p[i + 1]
yield p[1], p[0]
for c, d in iter_seg (p):
i = simu.utils.intersect.segment_segment (a, b, c, d)
if i is not None:
if found is not None:
found = min (found, i)
break
else:
found = i
return found
