# 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