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. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)compkl.c 8.1 (Berkeley) 5/31/93 34 * $FreeBSD: src/games/trek/compkl.c,v 1.4 1999/11/30 03:49:44 billf Exp $ 35 * $DragonFly: src/games/trek/compkl.c,v 1.3 2006/09/07 21:19:44 pavalos Exp $ 36 */ 37 38 # include "trek.h" 39 40 static void sortkl(void); 41 42 /* 43 ** compute klingon distances 44 ** 45 ** The klingon list has the distances for all klingons recomputed 46 ** and sorted. The parameter is a Boolean flag which is set if 47 ** we have just entered a new quadrant. 48 ** 49 ** This routine is used every time the Enterprise or the Klingons 50 ** move. 51 */ 52 53 void 54 compkldist(bool f) 55 { 56 int i, dx, dy; 57 double d; 58 double temp; 59 60 if (Etc.nkling == 0) 61 return; 62 for (i = 0; i < Etc.nkling; i++) 63 { 64 /* compute distance to the Klingon */ 65 dx = Ship.sectx - Etc.klingon[i].x; 66 dy = Ship.secty - Etc.klingon[i].y; 67 d = dx * dx + dy * dy; 68 d = sqrt(d); 69 70 /* compute average of new and old distances to Klingon */ 71 if (!f) 72 { 73 temp = Etc.klingon[i].dist; 74 Etc.klingon[i].avgdist = 0.5 * (temp + d); 75 } 76 else 77 { 78 /* new quadrant: average is current */ 79 Etc.klingon[i].avgdist = d; 80 } 81 Etc.klingon[i].dist = d; 82 } 83 84 /* leave them sorted */ 85 sortkl(); 86 } 87 88 89 /* 90 ** sort klingons 91 ** 92 ** bubble sort on ascending distance 93 */ 94 95 static void 96 sortkl(void) 97 { 98 struct kling t; 99 int f, i, m; 100 101 m = Etc.nkling - 1; 102 f = 1; 103 while (f) 104 { 105 f = 0; 106 for (i = 0; i < m; i++) 107 if (Etc.klingon[i].dist > Etc.klingon[i+1].dist) 108 { 109 bmove(&Etc.klingon[i], &t, sizeof t); 110 bmove(&Etc.klingon[i+1], &Etc.klingon[i], sizeof t); 111 bmove(&t, &Etc.klingon[i+1], sizeof t); 112 f = 1; 113 } 114 } 115 } 116