1 /* $NetBSD: compkl.c,v 1.4 1997/10/12 21:24:33 christos 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #ifndef lint 38 #if 0 39 static char sccsid[] = "@(#)compkl.c 8.1 (Berkeley) 5/31/93"; 40 #else 41 __RCSID("$NetBSD: compkl.c,v 1.4 1997/10/12 21:24:33 christos Exp $"); 42 #endif 43 #endif /* not lint */ 44 45 #include <math.h> 46 #include "trek.h" 47 48 /* 49 ** compute klingon distances 50 ** 51 ** The klingon list has the distances for all klingons recomputed 52 ** and sorted. The parameter is a Boolean flag which is set if 53 ** we have just entered a new quadrant. 54 ** 55 ** This routine is used every time the Enterprise or the Klingons 56 ** move. 57 */ 58 59 static void sortkl __P((void)); 60 61 void 62 compkldist(f) 63 int f; /* set if new quadrant */ 64 { 65 int i, dx, dy; 66 double d; 67 double temp; 68 69 if (Etc.nkling == 0) 70 return; 71 for (i = 0; i < Etc.nkling; i++) 72 { 73 /* compute distance to the Klingon */ 74 dx = Ship.sectx - Etc.klingon[i].x; 75 dy = Ship.secty - Etc.klingon[i].y; 76 d = dx * dx + dy * dy; 77 d = sqrt(d); 78 79 /* compute average of new and old distances to Klingon */ 80 if (!f) 81 { 82 temp = Etc.klingon[i].dist; 83 Etc.klingon[i].avgdist = 0.5 * (temp + d); 84 } 85 else 86 { 87 /* new quadrant: average is current */ 88 Etc.klingon[i].avgdist = d; 89 } 90 Etc.klingon[i].dist = d; 91 } 92 93 /* leave them sorted */ 94 sortkl(); 95 } 96 97 98 /* 99 ** sort klingons 100 ** 101 ** bubble sort on ascending distance 102 */ 103 104 static void 105 sortkl() 106 { 107 struct kling t; 108 int f, i, m; 109 110 m = Etc.nkling - 1; 111 f = 1; 112 while (f) 113 { 114 f = 0; 115 for (i = 0; i < m; i++) 116 if (Etc.klingon[i].dist > Etc.klingon[i+1].dist) 117 { 118 t = Etc.klingon[i]; 119 Etc.klingon[i] = Etc.klingon[i+1]; 120 Etc.klingon[i+1] = t; 121 f = 1; 122 } 123 } 124 } 125