1 /*- 2 * Copyright (c) 1980, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)compkl.c 8.1 (Berkeley) 5/31/93 30 * $FreeBSD: src/games/trek/compkl.c,v 1.4 1999/11/30 03:49:44 billf Exp $ 31 * $DragonFly: src/games/trek/compkl.c,v 1.3 2006/09/07 21:19:44 pavalos Exp $ 32 */ 33 34 #include "trek.h" 35 36 static void sortkl(void); 37 38 /* 39 ** compute klingon distances 40 ** 41 ** The klingon list has the distances for all klingons recomputed 42 ** and sorted. The parameter is a Boolean flag which is set if 43 ** we have just entered a new quadrant. 44 ** 45 ** This routine is used every time the Enterprise or the Klingons 46 ** move. 47 */ 48 49 void 50 compkldist(bool f) 51 { 52 int i, dx, dy; 53 double d; 54 double temp; 55 56 if (Etc.nkling == 0) 57 return; 58 for (i = 0; i < Etc.nkling; i++) { 59 /* compute distance to the Klingon */ 60 dx = Ship.sectx - Etc.klingon[i].x; 61 dy = Ship.secty - Etc.klingon[i].y; 62 d = dx * dx + dy * dy; 63 d = sqrt(d); 64 65 /* compute average of new and old distances to Klingon */ 66 if (!f) { 67 temp = Etc.klingon[i].dist; 68 Etc.klingon[i].avgdist = 0.5 * (temp + d); 69 } else { 70 /* new quadrant: average is current */ 71 Etc.klingon[i].avgdist = d; 72 } 73 Etc.klingon[i].dist = d; 74 } 75 76 /* leave them sorted */ 77 sortkl(); 78 } 79 80 81 /* 82 ** sort klingons 83 ** 84 ** bubble sort on ascending distance 85 */ 86 87 static void 88 sortkl(void) 89 { 90 struct kling t; 91 int f, i, m; 92 93 m = Etc.nkling - 1; 94 f = 1; 95 while (f) { 96 f = 0; 97 for (i = 0; i < m; i++) { 98 if (Etc.klingon[i].dist > Etc.klingon[i+1].dist) { 99 bmove(&Etc.klingon[i], &t, sizeof t); 100 bmove(&Etc.klingon[i+1], &Etc.klingon[i], sizeof t); 101 bmove(&t, &Etc.klingon[i+1], sizeof t); 102 f = 1; 103 } 104 } 105 } 106 } 107