/*
 * Copyright (c) 2005 by the Windstille team. All rights reserved.
 *
 * collision_test.cxx
 * by David Kamphausen (david.kamphausen@web.de)
 *    Ingo Ruhnke
 *
 * The "Windstille" project, including all files needed to compile it,
 * is free software; you can redistribute it and/or use 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.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program.
 */

#include "collision_test.hpp"
#include <assert.h>

SweepResult simple_sweep_1d(float a, float aw, float av,
			    float b, float bw, float bv)
{
  SweepResult res;
  // Normalize the calculation so that only A moves and B stands still
  float v = av - bv;

  if (v > 0)
    {
      res.t0 = (b - (a + aw)) / v;
      res.t1 = (b + bw - a) / v;
      res.state = SweepResult::COL_AT;

      assert(res.t0 <= res.t1);
    }
  else if (v < 0)
    {
      res.t0 = (b + bw - a) / v;
      res.t1 = (b - (a + aw)) / v;
      res.state = SweepResult::COL_AT;

      assert(res.t0 <= res.t1);
    }
  else // (v == 0)
    {
      if ((a + aw) < b || (a > b + bw))
        res.state = SweepResult::COL_NEVER;
      else
        res.state = SweepResult::COL_ALWAYS;
    }
  return res;
}

/* EOF */