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 are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 */ 17 18 #ifndef lint 19 static char sccsid[] = "@(#)compkl.c 5.3 (Berkeley) 06/18/88"; 20 #endif /* not lint */ 21 22 # include "trek.h" 23 24 /* 25 ** compute klingon distances 26 ** 27 ** The klingon list has the distances for all klingons recomputed 28 ** and sorted. The parameter is a Boolean flag which is set if 29 ** we have just entered a new quadrant. 30 ** 31 ** This routine is used every time the Enterprise or the Klingons 32 ** move. 33 */ 34 35 compkldist(f) 36 int f; /* set if new quadrant */ 37 { 38 register int i, dx, dy; 39 double d; 40 double temp; 41 42 if (Etc.nkling == 0) 43 return; 44 for (i = 0; i < Etc.nkling; i++) 45 { 46 /* compute distance to the Klingon */ 47 dx = Ship.sectx - Etc.klingon[i].x; 48 dy = Ship.secty - Etc.klingon[i].y; 49 d = dx * dx + dy * dy; 50 d = sqrt(d); 51 52 /* compute average of new and old distances to Klingon */ 53 if (!f) 54 { 55 temp = Etc.klingon[i].dist; 56 Etc.klingon[i].avgdist = 0.5 * (temp + d); 57 } 58 else 59 { 60 /* new quadrant: average is current */ 61 Etc.klingon[i].avgdist = d; 62 } 63 Etc.klingon[i].dist = d; 64 } 65 66 /* leave them sorted */ 67 sortkl(); 68 } 69 70 71 /* 72 ** sort klingons 73 ** 74 ** bubble sort on ascending distance 75 */ 76 77 sortkl() 78 { 79 struct kling t; 80 register int f, i, m; 81 82 m = Etc.nkling - 1; 83 f = 1; 84 while (f) 85 { 86 f = 0; 87 for (i = 0; i < m; i++) 88 if (Etc.klingon[i].dist > Etc.klingon[i+1].dist) 89 { 90 bmove(&Etc.klingon[i], &t, sizeof t); 91 bmove(&Etc.klingon[i+1], &Etc.klingon[i], sizeof t); 92 bmove(&t, &Etc.klingon[i+1], sizeof t); 93 f = 1; 94 } 95 } 96 } 97