1 /* $OpenBSD: compkl.c,v 1.8 2016/01/07 14:37:51 mestre Exp $ */ 2 /* $NetBSD: compkl.c,v 1.3 1995/04/22 10:58:38 cgd Exp $ */ 3 4 /* 5 * Copyright (c) 1980, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <math.h> 34 35 #include "trek.h" 36 37 /* 38 ** compute klingon distances 39 ** 40 ** The klingon list has the distances for all klingons recomputed 41 ** and sorted. The parameter is a Boolean flag which is set if 42 ** we have just entered a new quadrant. 43 ** 44 ** This routine is used every time the Enterprise or the Klingons 45 ** move. 46 */ 47 48 static void sortkl(void); 49 50 /* argument is set if new quadrant */ 51 void 52 compkldist(int f) 53 { 54 int i, dx, dy; 55 double d; 56 double temp; 57 58 if (Etc.nkling == 0) 59 return; 60 for (i = 0; i < Etc.nkling; i++) 61 { 62 /* compute distance to the Klingon */ 63 dx = Ship.sectx - Etc.klingon[i].x; 64 dy = Ship.secty - Etc.klingon[i].y; 65 d = dx * dx + dy * dy; 66 d = sqrt(d); 67 68 /* compute average of new and old distances to Klingon */ 69 if (!f) 70 { 71 temp = Etc.klingon[i].dist; 72 Etc.klingon[i].avgdist = 0.5 * (temp + d); 73 } 74 else 75 { 76 /* new quadrant: average is current */ 77 Etc.klingon[i].avgdist = d; 78 } 79 Etc.klingon[i].dist = d; 80 } 81 82 /* leave them sorted */ 83 sortkl(); 84 } 85 86 87 /* 88 ** sort klingons 89 ** 90 ** bubble sort on ascending distance 91 */ 92 93 static void 94 sortkl(void) 95 { 96 struct kling t; 97 int f, i, m; 98 99 m = Etc.nkling - 1; 100 f = 1; 101 while (f) 102 { 103 f = 0; 104 for (i = 0; i < m; i++) 105 if (Etc.klingon[i].dist > Etc.klingon[i+1].dist) 106 { 107 t = Etc.klingon[i]; 108 Etc.klingon[i] = Etc.klingon[i + 1]; 109 Etc.klingon[i + 1] = t; 110 f = 1; 111 } 112 } 113 } 114