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Diffstat (limited to 'host/simu/model/round_obstacle.py')

-rw-r--r-- | host/simu/model/round_obstacle.py | 54 |

1 files changed, 54 insertions, 0 deletions

diff --git a/host/simu/model/round_obstacle.py b/host/simu/model/round_obstacle.py new file mode 100644 index 00000000..fc0cfc6a --- /dev/null +++ b/host/simu/model/round_obstacle.py @@ -0,0 +1,54 @@ +# simu - Robot simulation. {{{ +# +# Copyright (C) 2009 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 round shape.""" +from math import pi, cos, sin, sqrt + +class RoundObstacle: + + def __init__ (self, radius, level = 0): + self.pos = None + self.radius = radius + 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.""" + ab = sqrt ((b[0] - a[0]) ** 2 + (b[1] - a[1]) ** 2) # distance AB. + n = ((b[0] - a[0]) / ab, (b[1] - a[1]) / ab) # vector of length 1. + o = self.pos # obstacle center. + # To check if the line (AB) intersects the circle, compute distance + # from circle center to line using a dot product. + vao = (o[0] - a[0], o[1] - a[1]) # vector AO. + # dot product, (-n[1], n[0]) is perpendicular to n. + doc = abs (vao[0] * -n[1] + vao[1] * n[0]) + if doc < self.radius: + # Line intersects, check if segment intersects. + m = vao[0] * n[0] + vao[1] * n[1] + f = sqrt (self.radius ** 2 - doc ** 2) + if m - f > 0 and m - f < ab: + return m - f + elif m + f > 0 and m + f < ab: + return m + f + return None + |