1 /* 2 * Copyright (c) 1980 Regents of the University of California. 3 * 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 34 #ifndef lint 35 /*static char sccsid[] = "from: @(#)compkl.c 5.4 (Berkeley) 6/1/90";*/ 36 static char rcsid[] = "$Id: compkl.c,v 1.2 1993/08/01 18:50:47 mycroft Exp $"; 37 #endif /* not lint */ 38 39 # include "trek.h" 40 41 /* 42 ** compute klingon distances 43 ** 44 ** The klingon list has the distances for all klingons recomputed 45 ** and sorted. The parameter is a Boolean flag which is set if 46 ** we have just entered a new quadrant. 47 ** 48 ** This routine is used every time the Enterprise or the Klingons 49 ** move. 50 */ 51 52 compkldist(f) 53 int f; /* set if new quadrant */ 54 { 55 register int i, dx, dy; 56 double d; 57 double temp; 58 59 if (Etc.nkling == 0) 60 return; 61 for (i = 0; i < Etc.nkling; i++) 62 { 63 /* compute distance to the Klingon */ 64 dx = Ship.sectx - Etc.klingon[i].x; 65 dy = Ship.secty - Etc.klingon[i].y; 66 d = dx * dx + dy * dy; 67 d = sqrt(d); 68 69 /* compute average of new and old distances to Klingon */ 70 if (!f) 71 { 72 temp = Etc.klingon[i].dist; 73 Etc.klingon[i].avgdist = 0.5 * (temp + d); 74 } 75 else 76 { 77 /* new quadrant: average is current */ 78 Etc.klingon[i].avgdist = d; 79 } 80 Etc.klingon[i].dist = d; 81 } 82 83 /* leave them sorted */ 84 sortkl(); 85 } 86 87 88 /* 89 ** sort klingons 90 ** 91 ** bubble sort on ascending distance 92 */ 93 94 sortkl() 95 { 96 struct kling t; 97 register 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 bmove(&Etc.klingon[i], &t, sizeof t); 108 bmove(&Etc.klingon[i+1], &Etc.klingon[i], sizeof t); 109 bmove(&t, &Etc.klingon[i+1], sizeof t); 110 f = 1; 111 } 112 } 113 } 114