#ifndef lint
-static char *sccsid = "@(#)misc.c 1.1 83/03/17";
+static char *sccsid = "@(#)misc.c 2.1 83/10/31";
#endif
#include "externs.h"
#define distance(x,y) (abs(x) >= abs(y) ? abs(x) + abs(y)/2 : abs(y) + abs(x)/2)
-range(fromship, toship)
-register int fromship, toship;
+/* XXX */
+range(from, to)
+struct ship *from, *to;
{
- int bow1r, bow1c, bow2r, bow2c;
- int stern1r, stern1c, stern2c, stern2r;
- register int bb, bs, sb, ss, result;
-
- if (fromship > scene[game].vessels
- || toship > scene[game].vessels) /* just in case */
- return(30000);
- if (!pos[toship].dir)
- return(30000);
- stern1r = bow1r = pos[fromship].row;
- stern1c = bow1c = pos[fromship].col;
- stern2r = bow2r = pos[toship].row;
- stern2c = bow2c = pos[toship].col;
- result = bb = distance((bow2r - bow1r), (bow2c - bow1c));
- if (bb < 5)
- {
- drdc(&stern2r, &stern2c, pos[toship].dir);
- drdc(&stern1r, &stern1c, pos[fromship].dir);
- bs = distance((bow2r - stern1r) ,(bow2c - stern1c));
- sb = distance((bow1r - stern2r) ,(bow1c - stern2c));
- ss = distance((stern2r - stern1r) ,(stern2c - stern1c));
- result = min(bb, min(bs, min(sb, ss)));
+ register bow1r, bow1c, bow2r, bow2c;
+ int stern1r, stern1c, stern2c, stern2r;
+ register int bb, bs, sb, ss, result;
+
+ if (!to->file->dir)
+ return -1;
+ stern1r = bow1r = from->file->row;
+ stern1c = bow1c = from->file->col;
+ stern2r = bow2r = to->file->row;
+ stern2c = bow2c = to->file->col;
+ result = bb = distance(bow2r - bow1r, bow2c - bow1c);
+ if (bb < 5) {
+ stern2r += dr[to->file->dir];
+ stern2c += dc[to->file->dir];
+ stern1r += dr[from->file->dir];
+ stern1c += dc[from->file->dir];
+ bs = distance((bow2r - stern1r), (bow2c - stern1c));
+ sb = distance((bow1r - stern2r), (bow1c - stern2c));
+ ss = distance((stern2r - stern1r) ,(stern2c - stern1c));
+ result = min(bb, min(bs, min(sb, ss)));
+ }
+ return result;
+}
+
+struct ship *
+closestenemy(from, side, anyship)
+register struct ship *from;
+char side, anyship;
+{
+ register struct ship *sp;
+ register char a;
+ int olddist = 30000, dist;
+ struct ship *closest = 0;
+
+ a = capship(from)->nationality;
+ foreachship(sp) {
+ if (sp == from)
+ continue;
+ if (sp->file->dir == 0)
+ continue;
+ if (a == capship(sp)->nationality && !anyship)
+ continue;
+ if (side && gunsbear(from, sp) != side)
+ continue;
+ dist = range(from, sp);
+ if (dist < olddist) {
+ closest = sp;
+ olddist = dist;
+ }
+ }
+ return closest;
+}
+
+angle(dr, dc)
+register dr, dc;
+{
+ register i;
+
+ if (dc >= 0 && dr > 0)
+ i = 0;
+ else if (dr <= 0 && dc > 0)
+ i = 2;
+ else if (dc <= 0 && dr < 0)
+ i = 4;
+ else
+ i = 6;
+ dr = abs(dr);
+ dc = abs(dc);
+ if ((i == 0 || i == 4) && dc * 2.4 > dr) {
+ i++;
+ if (dc > dr * 2.4)
+ i++;
+ } else if ((i == 2 || i == 6) && dr * 2.4 > dc) {
+ i++;
+ if (dr > dc * 2.4)
+ i++;
}
- return(result);
+ return i % 8 + 1;
}
-drdc(dr, dc, dir)
-register int *dr, *dc;
-int dir;
+gunsbear(from, to) /* checks for target bow or stern */
+register struct ship *from, *to;
{
- switch (dir)
- {
- case 1:
- (*dr)++;
- break;
- case 2:
- (*dr)++;
- (*dc)--;
- break;
- case 3:
- (*dc)--;
- break;
- case 4:
- (*dr)--;
- (*dc)--;
- break;
- case 5:
- (*dr)--;
- break;
- case 6:
- (*dr)--;
- (*dc)++;
- break;
- case 7:
- (*dc)++;
- break;
- case 8:
- (*dr)++;
- (*dc)++;
- break;
+ int Dr, Dc, i;
+ register ang;
+
+ Dr = from->file->row - to->file->row;
+ Dc = to->file->col - from->file->col;
+ for (i = 2; i; i--) {
+ if ((ang = angle(Dr, Dc) - from->file->dir + 1) < 1)
+ ang += 8;
+ if (ang >= 2 && ang <= 4)
+ return 'r';
+ if (ang >= 6 && ang <= 7)
+ return 'l';
+ Dr += dr[to->file->dir];
+ Dc += dc[to->file->dir];
+ }
+ return 0;
+}
+
+portside(from, on, quick)
+register struct ship *from, *on;
+int quick; /* returns true if fromship is */
+{ /* shooting at onship's starboard side */
+ register ang;
+ register Dr, Dc;
+
+ Dr = from->file->row - on->file->row;
+ Dc = on->file->col - from->file->col;
+ if (quick == -1) {
+ Dr += dr[on->file->dir];
+ Dc += dc[on->file->dir];
}
+ ang = angle(Dr, Dc);
+ if (quick != 0)
+ return ang;
+ ang = (ang + 4 - on->file->dir - 1) % 8 + 1;
+ return ang < 5;
+}
+
+colours(sp)
+register struct ship *sp;
+{
+ register char flag;
+
+ if (sp->file->struck)
+ flag = '!';
+ if (sp->file->explode)
+ flag = '#';
+ if (sp->file->sink)
+ flag = '~';
+ if (sp->file->struck)
+ return flag;
+ flag = *countryname[capship(sp)->nationality];
+ return sp->file->FS ? flag : tolower(flag);
+}
+
+#ifdef notdef
+#define PI 3.1415926535
+
+float contable[8] =
+ { 1.5708, 0.7854, 0.0, -0.7854, -1.5708, -2.3562, -PI, 2.3562 };
+
+int tantable[40] = {
+ 0,100,197,291,381,
+ 464,540,610,675,733,
+ 785,833,876,915,951,
+ 983,1012,1039,1064,1086,
+ 1107,1126,1144,1161,1176,
+ 1190,1204,1216,1227,1239,
+ 1249,1259,1268,1277,1285,
+ 1293,1300,1307,1313,1470
+};
+
+double
+arctan(y,x)
+int y,x;
+{
+ int sx, sy;
+ register int index;
+
+ sy = y < 0 ? -1 : 1;
+ sx = x < 0 ? -1 : 1;
+ y *= sy;
+ x *= sx;
+ if (!x)
+ return (double) PI/2 * sy;
+ index = 10 * y / x + 0.5;
+ if (index > 39)
+ index = 39;
+ return (double)
+ sy * (sx < 0 ? PI : 0 + sx*((float)tantable[index]/1000));
}
+#endif