# inter - Robot simulation interface. {{{ # # Copyright (C) 2008 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. # # }}} """Distance sensor.""" from math import pi, cos, sin, sqrt from Tkinter import * from simu.inter.drawable import * from utils.observable import Observable class DistSensor (Drawable, Observable): """A distance sensor.""" def __init__ (self, onto, pos, angle, range): Drawable.__init__ (self, onto) Observable.__init__ (self) self.onto = onto self.pos = pos self.angle = angle self.range = range self.target = (pos[0] + cos (angle) * range, pos[1] + sin (angle) * range) self.obstacles = [ ] self.distance = None self.hide = False def compute (self): # Could do better by trans_applying until on the same drawable as the # obstacle. pos = self.onto.trans_apply (self.pos) target = self.onto.trans_apply (self.target) n = ((target[0] - pos[0]) / self.range, (target[1] - pos[1]) / self.range) self.distance = None for o in self.obstacles: # Does the line intersect with the obstacle? ao = (o.pos[0] - pos[0], o.pos[1] - pos[1]) doc = abs (ao[0] * -n[1] + ao[1] * n[0]) if doc < o.radius: # Does the segment intersect? m = ao[0] * n[0] + ao[1] * n[1] f = sqrt (o.radius ** 2 - doc ** 2) if m - f > 0 and m - f < self.range: d = m - f if self.distance is None or self.distance > d: self.distance = d elif m + f > 0 and m + f < self.range: d = m + f if self.distance is None or self.distance > d: self.distance = d self.notify () return self.distance def draw (self): self.compute () self.reset () if self.hide: return if self.distance is None: self.draw_line (self.pos, self.target, fill = 'blue', arrow = LAST) else: inter = (self.pos[0] + cos (self.angle) * self.distance, self.pos[1] + sin (self.angle) * self.distance) self.draw_line (self.pos, inter, fill = 'red', arrow = LAST) self.draw_line (inter, self.target, fill = 'blue', arrow = LAST)