# simu - Robot simulation. {{{
#
# Copyright (C) 2011 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 02111-1307, USA.
#
# }}}
"""Obstacle with a rectangular shape."""
from utils.observable import Observable
from simu.utils.vector import vector
from math import pi
import simu.utils.intersect
class RectangularObstacle (Observable):
def __init__ (self, dim, level = 0):
Observable.__init__ (self)
self.pos = None
self.angle = 0
self.dim = dim
self.level = level
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 rectangle segments. There is at most
# two intersections, return the nearest.
u = vector.polar (self.angle, self.dim[0] / 2.)
v = vector.polar (self.angle + pi / 2, self.dim[1] / 2.)
o = vector (self.pos)
p1 = o + u + v
p2 = o - u + v
p3 = o - u - v
p4 = o + u - v
found = None
for c, d in ((p1, p2), (p2, p3), (p3, p4), (p4, p1)):
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