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1 | /* |
2 | * Copyright (c) 1980 Regents of the University of California. | |
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3 | * All rights reserved. |
4 | * | |
5 | * Redistribution and use in source and binary forms are permitted | |
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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. | |
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16 | */ |
17 | ||
f67257fc | 18 | #ifndef lint |
d99e6414 | 19 | static char sccsid[] = "@(#)compkl.c 5.3 (Berkeley) %G%"; |
e9fb6bea | 20 | #endif /* not lint */ |
f67257fc KM |
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 | } | |
f67257fc | 96 | } |