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/* $OpenBSD: compkl.c,v 1.6 2009/10/27 23:59:27 deraadt Exp $ */
/* $NetBSD: compkl.c,v 1.3 1995/04/22 10:58:38 cgd Exp $ */
/*
* Copyright (c) 1980, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name of the University 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 REGENTS 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
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <math.h>
#include "trek.h"
/*
** compute klingon distances
**
** The klingon list has the distances for all klingons recomputed
** and sorted. The parameter is a Boolean flag which is set if
** we have just entered a new quadrant.
**
** This routine is used every time the Enterprise or the Klingons
** move.
*/
static void sortkl(void);
void
compkldist(f)
int f; /* set if new quadrant */
{
int i, dx, dy;
double d;
double temp;
if (Etc.nkling == 0)
return;
for (i = 0; i < Etc.nkling; i++)
{
/* compute distance to the Klingon */
dx = Ship.sectx - Etc.klingon[i].x;
dy = Ship.secty - Etc.klingon[i].y;
d = dx * dx + dy * dy;
d = sqrt(d);
/* compute average of new and old distances to Klingon */
if (!f)
{
temp = Etc.klingon[i].dist;
Etc.klingon[i].avgdist = 0.5 * (temp + d);
}
else
{
/* new quadrant: average is current */
Etc.klingon[i].avgdist = d;
}
Etc.klingon[i].dist = d;
}
/* leave them sorted */
sortkl();
}
/*
** sort klingons
**
** bubble sort on ascending distance
*/
static void
sortkl()
{
struct kling t;
int f, i, m;
m = Etc.nkling - 1;
f = 1;
while (f)
{
f = 0;
for (i = 0; i < m; i++)
if (Etc.klingon[i].dist > Etc.klingon[i+1].dist)
{
t = Etc.klingon[i];
Etc.klingon[i] = Etc.klingon[i + 1];
Etc.klingon[i + 1] = t;
f = 1;
}
}
}
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