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f67257fc KM |
1 | #ifndef lint |
2 | static char sccsid[] = "@(#)compkl.c 4.1 (Berkeley) %G%"; | |
3 | #endif not lint | |
4 | ||
5 | # include "trek.h" | |
6 | ||
7 | /* | |
8 | ** compute klingon distances | |
9 | ** | |
10 | ** The klingon list has the distances for all klingons recomputed | |
11 | ** and sorted. The parameter is a Boolean flag which is set if | |
12 | ** we have just entered a new quadrant. | |
13 | ** | |
14 | ** This routine is used every time the Enterprise or the Klingons | |
15 | ** move. | |
16 | */ | |
17 | ||
18 | compkldist(f) | |
19 | int f; /* set if new quadrant */ | |
20 | { | |
21 | register int i, dx, dy; | |
22 | double d; | |
23 | double temp; | |
24 | ||
25 | if (Etc.nkling == 0) | |
26 | return; | |
27 | for (i = 0; i < Etc.nkling; i++) | |
28 | { | |
29 | /* compute distance to the Klingon */ | |
30 | dx = Ship.sectx - Etc.klingon[i].x; | |
31 | dy = Ship.secty - Etc.klingon[i].y; | |
32 | d = dx * dx + dy * dy; | |
33 | d = sqrt(d); | |
34 | ||
35 | /* compute average of new and old distances to Klingon */ | |
36 | if (!f) | |
37 | { | |
38 | temp = Etc.klingon[i].dist; | |
39 | Etc.klingon[i].avgdist = 0.5 * (temp + d); | |
40 | } | |
41 | else | |
42 | { | |
43 | /* new quadrant: average is current */ | |
44 | Etc.klingon[i].avgdist = d; | |
45 | } | |
46 | Etc.klingon[i].dist = d; | |
47 | } | |
48 | ||
49 | /* leave them sorted */ | |
50 | sortkl(); | |
51 | } | |
52 | ||
53 | ||
54 | /* | |
55 | ** sort klingons | |
56 | ** | |
57 | ** bubble sort on ascending distance | |
58 | */ | |
59 | ||
60 | sortkl() | |
61 | { | |
62 | struct kling t; | |
63 | register int f, i, m; | |
64 | ||
65 | m = Etc.nkling - 1; | |
66 | f = 1; | |
67 | while (f) | |
68 | { | |
69 | f = 0; | |
70 | for (i = 0; i < m; i++) | |
71 | if (Etc.klingon[i].dist > Etc.klingon[i+1].dist) | |
72 | { | |
73 | bmove(&Etc.klingon[i], &t, sizeof t); | |
74 | bmove(&Etc.klingon[i+1], &Etc.klingon[i], sizeof t); | |
75 | bmove(&t, &Etc.klingon[i+1], sizeof t); | |
76 | f = 1; | |
77 | } | |
78 | } | |
79 | return; | |
80 | } |