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b6f0a7e4 DF |
1 | /* |
2 | * Copyright (c) 1980 Regents of the University of California. | |
3 | * All rights reserved. The Berkeley software License Agreement | |
4 | * specifies the terms and conditions for redistribution. | |
5 | */ | |
6 | ||
f67257fc | 7 | #ifndef lint |
b6f0a7e4 | 8 | static char sccsid[] = "@(#)compkl.c 5.1 (Berkeley) %G%"; |
f67257fc KM |
9 | #endif not lint |
10 | ||
11 | # include "trek.h" | |
12 | ||
13 | /* | |
14 | ** compute klingon distances | |
15 | ** | |
16 | ** The klingon list has the distances for all klingons recomputed | |
17 | ** and sorted. The parameter is a Boolean flag which is set if | |
18 | ** we have just entered a new quadrant. | |
19 | ** | |
20 | ** This routine is used every time the Enterprise or the Klingons | |
21 | ** move. | |
22 | */ | |
23 | ||
24 | compkldist(f) | |
25 | int f; /* set if new quadrant */ | |
26 | { | |
27 | register int i, dx, dy; | |
28 | double d; | |
29 | double temp; | |
30 | ||
31 | if (Etc.nkling == 0) | |
32 | return; | |
33 | for (i = 0; i < Etc.nkling; i++) | |
34 | { | |
35 | /* compute distance to the Klingon */ | |
36 | dx = Ship.sectx - Etc.klingon[i].x; | |
37 | dy = Ship.secty - Etc.klingon[i].y; | |
38 | d = dx * dx + dy * dy; | |
39 | d = sqrt(d); | |
40 | ||
41 | /* compute average of new and old distances to Klingon */ | |
42 | if (!f) | |
43 | { | |
44 | temp = Etc.klingon[i].dist; | |
45 | Etc.klingon[i].avgdist = 0.5 * (temp + d); | |
46 | } | |
47 | else | |
48 | { | |
49 | /* new quadrant: average is current */ | |
50 | Etc.klingon[i].avgdist = d; | |
51 | } | |
52 | Etc.klingon[i].dist = d; | |
53 | } | |
54 | ||
55 | /* leave them sorted */ | |
56 | sortkl(); | |
57 | } | |
58 | ||
59 | ||
60 | /* | |
61 | ** sort klingons | |
62 | ** | |
63 | ** bubble sort on ascending distance | |
64 | */ | |
65 | ||
66 | sortkl() | |
67 | { | |
68 | struct kling t; | |
69 | register int f, i, m; | |
70 | ||
71 | m = Etc.nkling - 1; | |
72 | f = 1; | |
73 | while (f) | |
74 | { | |
75 | f = 0; | |
76 | for (i = 0; i < m; i++) | |
77 | if (Etc.klingon[i].dist > Etc.klingon[i+1].dist) | |
78 | { | |
79 | bmove(&Etc.klingon[i], &t, sizeof t); | |
80 | bmove(&Etc.klingon[i+1], &Etc.klingon[i], sizeof t); | |
81 | bmove(&t, &Etc.klingon[i+1], sizeof t); | |
82 | f = 1; | |
83 | } | |
84 | } | |
f67257fc | 85 | } |