trek/move.c

   1 /*      $NetBSD: move.c,v 1.6 2003/08/07 09:37:52 agc Exp $     */
   2
   3 /*
   4  * Copyright (c) 1980, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #ifndef lint
  34 #if 0
  35 static char sccsid[] = "@(#)move.c      8.1 (Berkeley) 5/31/93";
  36 #else
  37 __RCSID("$NetBSD: move.c,v 1.6 2003/08/07 09:37:52 agc Exp $");
  38 #endif
  39 #endif /* not lint */
  40
  41 #include <stdio.h>
  42 #include <math.h>
  43 #include "trek.h"
  44
  45 /*
  46 **  Move Under Warp or Impulse Power
  47 **
  48 **      `Ramflag' is set if we are to be allowed to ram stars,
  49 **      Klingons, etc.  This is passed from warp(), which gets it from
  50 **      either play() or ram().  Course is the course (0 -> 360) at
  51 **      which we want to move.  `Speed' is the speed we
  52 **      want to go, and `time' is the expected time.  It
  53 **      can get cut short if a long range tractor beam is to occur.  We
  54 **      cut short the move so that the user doesn't get docked time and
  55 **      energy for distance which he didn't travel.
  56 **
  57 **      We check the course through the current quadrant to see that he
  58 **      doesn't run into anything.  After that, though, space sort of
  59 **      bends around him.  Note that this puts us in the awkward posi-
  60 **      tion of being able to be dropped into a sector which is com-
  61 **      pletely surrounded by stars.  Oh Well.
  62 **
  63 **      If the SINS (Space Inertial Navigation System) is out, we ran-
  64 **      domize the course accordingly before ever starting to move.
  65 **      We will still move in a straight line.
  66 **
  67 **      Note that if your computer is out, you ram things anyway.  In
  68 **      other words, if your computer and sins are both out, you're in
  69 **      potentially very bad shape.
  70 **
  71 **      Klingons get a chance to zap you as you leave the quadrant.
  72 **      By the way, they also try to follow you (heh heh).
  73 **
  74 **      Return value is the actual amount of time used.
  75 **
  76 **
  77 **      Uses trace flag 4.
  78 */
  79
  80 double move(ramflag, course, time, speed)
  81 int     ramflag;
  82 int     course;
  83 double  time;
  84 double  speed;
  85 {
  86         double                  angle;
  87         double                  x, y, dx, dy;
  88         int             ix = 0, iy = 0;
  89         double                  bigger;
  90         int                     n;
  91         int             i;
  92         double                  dist;
  93         double                  sectsize;
  94         double                  xn;
  95         double                  evtime;
  96
  97 #       ifdef xTRACE
  98         if (Trace)
  99                 printf("move: ramflag %d course %d time %.2f speed %.2f\n",
 100                         ramflag, course, time, speed);
 101 #       endif
 102         sectsize = NSECTS;
 103         /* initialize delta factors for move */
 104         angle = course * 0.0174532925;
 105         if (damaged(SINS))
 106                 angle += Param.navigcrud[1] * (franf() - 0.5);
 107         else
 108                 if (Ship.sinsbad)
 109                         angle += Param.navigcrud[0] * (franf() - 0.5);
 110         dx = -cos(angle);
 111         dy = sin(angle);
 112         bigger = fabs(dx);
 113         dist = fabs(dy);
 114         if (dist > bigger)
 115                 bigger = dist;
 116         dx /= bigger;
 117         dy /= bigger;
 118
 119         /* check for long range tractor beams */
 120         /****  TEMPORARY CODE == DEBUGGING  ****/
 121         evtime = Now.eventptr[E_LRTB]->date - Now.date;
 122 #       ifdef xTRACE
 123         if (Trace)
 124                 printf("E.ep = %p, ->evcode = %d, ->date = %.2f, evtime = %.2f\n",
 125                         Now.eventptr[E_LRTB], Now.eventptr[E_LRTB]->evcode,
 126                         Now.eventptr[E_LRTB]->date, evtime);
 127 #       endif
 128         if (time > evtime && Etc.nkling < 3)
 129         {
 130                 /* then we got a LRTB */
 131                 evtime += 0.005;
 132                 time = evtime;
 133         }
 134         else
 135                 evtime = -1.0e50;
 136         dist = time * speed;
 137
 138         /* move within quadrant */
 139         Sect[Ship.sectx][Ship.secty] = EMPTY;
 140         x = Ship.sectx + 0.5;
 141         y = Ship.secty + 0.5;
 142         xn = NSECTS * dist * bigger;
 143         n = xn + 0.5;
 144 #       ifdef xTRACE
 145         if (Trace)
 146                 printf("dx = %.2f, dy = %.2f, xn = %.2f, n = %d\n", dx, dy, xn, n);
 147 #       endif
 148         Move.free = 0;
 149
 150         for (i = 0; i < n; i++)
 151         {
 152                 ix = (x += dx);
 153                 iy = (y += dy);
 154 #               ifdef xTRACE
 155                 if (Trace)
 156                         printf("ix = %d, x = %.2f, iy = %d, y = %.2f\n", ix, x, iy, y);
 157 #               endif
 158                 if (x < 0.0 || y < 0.0 || x >= sectsize || y >= sectsize)
 159                 {
 160                         /* enter new quadrant */
 161                         dx = Ship.quadx * NSECTS + Ship.sectx + dx * xn;
 162                         dy = Ship.quady * NSECTS + Ship.secty + dy * xn;
 163                         if (dx < 0.0)
 164                                 ix = -1;
 165                         else
 166                                 ix = dx + 0.5;
 167                         if (dy < 0.0)
 168                                 iy = -1;
 169                         else
 170                                 iy = dy + 0.5;
 171 #                       ifdef xTRACE
 172                         if (Trace)
 173                                 printf("New quad: ix = %d, iy = %d\n", ix, iy);
 174 #                       endif
 175                         Ship.sectx = x;
 176                         Ship.secty = y;
 177                         compkldist(0);
 178                         Move.newquad = 2;
 179                         attack(0);
 180                         checkcond();
 181                         Ship.quadx = ix / NSECTS;
 182                         Ship.quady = iy / NSECTS;
 183                         Ship.sectx = ix % NSECTS;
 184                         Ship.secty = iy % NSECTS;
 185                         if (ix < 0 || Ship.quadx >= NQUADS || iy < 0 ||
 186                             Ship.quady >= NQUADS) {
 187                                 if (!damaged(COMPUTER)) {
 188                                         dumpme(0);
 189                                 } else
 190                                         lose(L_NEGENB);
 191                         }
 192                         initquad(0);
 193                         n = 0;
 194                         break;
 195                 }
 196                 if (Sect[ix][iy] != EMPTY)
 197                 {
 198                         /* we just hit something */
 199                         if (!damaged(COMPUTER) && ramflag <= 0)
 200                         {
 201                                 ix = x - dx;
 202                                 iy = y - dy;
 203                                 printf("Computer reports navigation error; %s stopped at %d,%d\n",
 204                                         Ship.shipname, ix, iy);
 205                                 Ship.energy -= Param.stopengy * speed;
 206                                 break;
 207                         }
 208                         /* test for a black hole */
 209                         if (Sect[ix][iy] == HOLE)
 210                         {
 211                                 /* get dumped elsewhere in the galaxy */
 212                                 dumpme(1);
 213                                 initquad(0);
 214                                 n = 0;
 215                                 break;
 216                         }
 217                         ram(ix, iy);
 218                         break;
 219                 }
 220         }
 221         if (n > 0)
 222         {
 223                 dx = Ship.sectx - ix;
 224                 dy = Ship.secty - iy;
 225                 dist = sqrt(dx * dx + dy * dy) / NSECTS;
 226                 time = dist / speed;
 227                 if (evtime > time)
 228                         time = evtime;          /* spring the LRTB trap */
 229                 Ship.sectx = ix;
 230                 Ship.secty = iy;
 231         }
 232         Sect[Ship.sectx][Ship.secty] = Ship.ship;
 233         compkldist(0);
 234         return (time);
 235 }