1 /* $NetBSD: compkl.c,v 1.6 2004/01/27 20:30:30 jsm 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 35 static char sccsid[] = "@(#)compkl.c 8.1 (Berkeley) 5/31/93"; 36 #else 37 __RCSID("$NetBSD: compkl.c,v 1.6 2004/01/27 20:30:30 jsm 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 55 static void sortkl(void); 56 57 void 58 compkldist(f) 59 int f; /* set if new quadrant */ 60 { 61 int i, dx, dy; 62 double d; 63 double temp; 64 65 if (Etc.nkling == 0) 66 return; 67 for (i = 0; i < Etc.nkling; i++) 68 { 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 { 78 temp = Etc.klingon[i].dist; 79 Etc.klingon[i].avgdist = 0.5 * (temp + d); 80 } 81 else 82 { 83 /* new quadrant: average is current */ 84 Etc.klingon[i].avgdist = d; 85 } 86 Etc.klingon[i].dist = d; 87 } 88 89 /* leave them sorted */ 90 sortkl(); 91 } 92 93 94 /* 95 ** sort klingons 96 ** 97 ** bubble sort on ascending distance 98 */ 99 100 static void 101 sortkl() 102 { 103 struct kling t; 104 int f, i, m; 105 106 m = Etc.nkling - 1; 107 f = 1; 108 while (f) 109 { 110 f = 0; 111 for (i = 0; i < m; i++) 112 if (Etc.klingon[i].dist > Etc.klingon[i+1].dist) 113 { 114 t = Etc.klingon[i]; 115 Etc.klingon[i] = Etc.klingon[i+1]; 116 Etc.klingon[i+1] = t; 117 f = 1; 118 } 119 } 120 } 121