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Annotation of 43BSDTahoe/games/trek/compkl.c, revision 1.1.1.1

1.1       root        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) 6/18/88";
                     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: }

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