# 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 02111-1307, 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