1 /* 2 * Copyright (c) 1980, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 */ 7 8 #ifndef lint 9 static char sccsid[] = "@(#)compkl.c 8.1 (Berkeley) 05/31/93"; 10 #endif /* not lint */ 11 12 # include "trek.h" 13 14 /* 15 ** compute klingon distances 16 ** 17 ** The klingon list has the distances for all klingons recomputed 18 ** and sorted. The parameter is a Boolean flag which is set if 19 ** we have just entered a new quadrant. 20 ** 21 ** This routine is used every time the Enterprise or the Klingons 22 ** move. 23 */ 24 25 compkldist(f) 26 int f; /* set if new quadrant */ 27 { 28 register int i, dx, dy; 29 double d; 30 double temp; 31 32 if (Etc.nkling == 0) 33 return; 34 for (i = 0; i < Etc.nkling; i++) 35 { 36 /* compute distance to the Klingon */ 37 dx = Ship.sectx - Etc.klingon[i].x; 38 dy = Ship.secty - Etc.klingon[i].y; 39 d = dx * dx + dy * dy; 40 d = sqrt(d); 41 42 /* compute average of new and old distances to Klingon */ 43 if (!f) 44 { 45 temp = Etc.klingon[i].dist; 46 Etc.klingon[i].avgdist = 0.5 * (temp + d); 47 } 48 else 49 { 50 /* new quadrant: average is current */ 51 Etc.klingon[i].avgdist = d; 52 } 53 Etc.klingon[i].dist = d; 54 } 55 56 /* leave them sorted */ 57 sortkl(); 58 } 59 60 61 /* 62 ** sort klingons 63 ** 64 ** bubble sort on ascending distance 65 */ 66 67 sortkl() 68 { 69 struct kling t; 70 register int f, i, m; 71 72 m = Etc.nkling - 1; 73 f = 1; 74 while (f) 75 { 76 f = 0; 77 for (i = 0; i < m; i++) 78 if (Etc.klingon[i].dist > Etc.klingon[i+1].dist) 79 { 80 bmove(&Etc.klingon[i], &t, sizeof t); 81 bmove(&Etc.klingon[i+1], &Etc.klingon[i], sizeof t); 82 bmove(&t, &Etc.klingon[i+1], sizeof t); 83 f = 1; 84 } 85 } 86 } 87