costmap_math.cpp

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/*
 * Copyright (c) 2013, Willow Garage, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
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 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Willow Garage, Inc. nor the names of its
 *       contributors may be used to endorse or promote products derived from
 *       this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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#include <costmap_2d/costmap_math.h>
 
double distanceToLine(double pX, double pY, double x0, double y0, double x1, double y1)
{
  double A = pX - x0;
  double B = pY - y0;
  double C = x1 - x0;
  double D = y1 - y0;
 
  double dot = A * C + B * D;
  double len_sq = C * C + D * D;
  double param = dot / len_sq;
 
  double xx, yy;
 
  if (param < 0)
  {
    xx = x0;
    yy = y0;
  }
  else if (param > 1)
  {
    xx = x1;
    yy = y1;
  }
  else
  {
    xx = x0 + param * C;
    yy = y0 + param * D;
  }
 
  return distance(pX, pY, xx, yy);
}
 
bool intersects(std::vector<geometry_msgs::Point>& polygon, float testx, float testy)
{
  bool c = false;
  int i, j, nvert = polygon.size();
  for (i = 0, j = nvert - 1; i < nvert; j = i++)
  {
    float yi = polygon[i].y, yj = polygon[j].y, xi = polygon[i].x, xj = polygon[j].x;
 
    if (((yi > testy) != (yj > testy)) && (testx < (xj - xi) * (testy - yi) / (yj - yi) + xi))
      c = !c;
  }
  return c;
}
 
bool intersects_helper(std::vector<geometry_msgs::Point>& polygon1, std::vector<geometry_msgs::Point>& polygon2)
{
  for (unsigned int i = 0; i < polygon1.size(); i++)
    if (intersects(polygon2, polygon1[i].x, polygon1[i].y))
      return true;
  return false;
}
 
bool intersects(std::vector<geometry_msgs::Point>& polygon1, std::vector<geometry_msgs::Point>& polygon2)
{
  return intersects_helper(polygon1, polygon2) || intersects_helper(polygon2, polygon1);
}