1/* $NetBSD: compkl.c,v 1.7 2009/05/24 19:18:44 dholland Exp $ */ 2 3/* 4 * Copyright (c) 1980, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32#include <sys/cdefs.h> 33#ifndef lint 34#if 0 35static char sccsid[] = "@(#)compkl.c 8.1 (Berkeley) 5/31/93"; 36#else 37__RCSID("$NetBSD: compkl.c,v 1.7 2009/05/24 19:18:44 dholland Exp $"); 38#endif 39#endif /* not lint */ 40 41#include <math.h> 42#include "trek.h" 43 44/* 45** compute klingon distances 46** 47** The klingon list has the distances for all klingons recomputed 48** and sorted. The parameter is a Boolean flag which is set if 49** we have just entered a new quadrant. 50** 51** This routine is used every time the Enterprise or the Klingons 52** move. 53** 54** f -- set if new quadrant 55*/ 56 57static void sortkl(void); 58 59void 60compkldist(int f) 61{ 62 int i, dx, dy; 63 double d; 64 double temp; 65 66 if (Etc.nkling == 0) 67 return; 68 for (i = 0; i < Etc.nkling; i++) { 69 /* compute distance to the Klingon */ 70 dx = Ship.sectx - Etc.klingon[i].x; 71 dy = Ship.secty - Etc.klingon[i].y; 72 d = dx * dx + dy * dy; 73 d = sqrt(d); 74 75 /* compute average of new and old distances to Klingon */ 76 if (!f) { 77 temp = Etc.klingon[i].dist; 78 Etc.klingon[i].avgdist = 0.5 * (temp + d); 79 } else { 80 /* new quadrant: average is current */ 81 Etc.klingon[i].avgdist = d; 82 } 83 Etc.klingon[i].dist = d; 84 } 85 86 /* leave them sorted */ 87 sortkl(); 88} 89 90 91/* 92** sort klingons 93** 94** bubble sort on ascending distance 95*/ 96 97static void 98sortkl(void) 99{ 100 struct kling t; 101 int f, i, m; 102 103 m = Etc.nkling - 1; 104 f = 1; 105 while (f) { 106 f = 0; 107 for (i = 0; i < m; i++) { 108 if (Etc.klingon[i].dist > Etc.klingon[i+1].dist) { 109 t = Etc.klingon[i]; 110 Etc.klingon[i] = Etc.klingon[i+1]; 111 Etc.klingon[i+1] = t; 112 f = 1; 113 } 114 } 115 } 116} 117