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authorNicolas Schodet2009-04-30 23:59:19 +0200
committerNicolas Schodet2009-04-30 23:59:19 +0200
commitba61bc0aba21e0bf9d1c845b6594ad1db2dd719d (patch)
tree53c9250b4e569ade74b9ccbf33e506aa77cf6bf3 /host/simu/model/round_obstacle.py
parent69305ae1ed6da084b6ee65dba3ce44f0d6cbe2d1 (diff)
* host/simu:
- added table model, round obstacle and generic distance sensor.
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+# 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
+