trek/move.c

   1 /*      $NetBSD: move.c,v 1.11 2011/07/03 06:44:01 mrg 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 1.11 2011/07/03 06:44:01 mrg Exp $");
  38 #endif
  39 #endif /* not lint */
  40
  41 #include <stdio.h>
  42 #include <math.h>
  43 #include <float.h>
  44 #include "trek.h"
  45
  46 /*
  47 **  Move Under Warp or Impulse Power
  48 **
  49 **      `Ramflag' is set if we are to be allowed to ram stars,
  50 **      Klingons, etc.  This is passed from warp(), which gets it from
  51 **      either play() or ram().  Course is the course (0 -> 360) at
  52 **      which we want to move.  `Speed' is the speed we
  53 **      want to go, and `time' is the expected time.  It
  54 **      can get cut short if a long range tractor beam is to occur.  We
  55 **      cut short the move so that the user doesn't get docked time and
  56 **      energy for distance which he didn't travel.
  57 **
  58 **      We check the course through the current quadrant to see that he
  59 **      doesn't run into anything.  After that, though, space sort of
  60 **      bends around him.  Note that this puts us in the awkward posi-
  61 **      tion of being able to be dropped into a sector which is com-
  62 **      pletely surrounded by stars.  Oh Well.
  63 **
  64 **      If the SINS (Space Inertial Navigation System) is out, we ran-
  65 **      domize the course accordingly before ever starting to move.
  66 **      We will still move in a straight line.
  67 **
  68 **      Note that if your computer is out, you ram things anyway.  In
  69 **      other words, if your computer and sins are both out, you're in
  70 **      potentially very bad shape.
  71 **
  72 **      Klingons get a chance to zap you as you leave the quadrant.
  73 **      By the way, they also try to follow you (heh heh).
  74 **
  75 **      Return value is the actual amount of time used.
  76 **
  77 **
  78 **      Uses trace flag 4.
  79 */
  80
  81 double
  82 move(int ramflag, int course, double time, double speed)
  83 {
  84         double                  angle;
  85         double                  x, y, dx, dy;
  86         int             ix = 0, iy = 0;
  87         double                  bigger;
  88         int                     n;
  89         int             i;
  90         double                  dist;
  91         double                  sectsize;
  92         double                  xn;
  93         double                  evtime;
  94
  95 #ifdef xTRACE
  96         if (Trace)
  97                 printf("move: ramflag %d course %d time %.2f speed %.2f\n",
  98                         ramflag, course, time, speed);
  99 #endif
 100         sectsize = NSECTS;
 101         /* initialize delta factors for move */
 102         angle = course * 0.0174532925;
 103         if (damaged(SINS))
 104                 angle += Param.navigcrud[1] * (franf() - 0.5);
 105         else
 106                 if (Ship.sinsbad)
 107                         angle += Param.navigcrud[0] * (franf() - 0.5);
 108         dx = -cos(angle);
 109         dy = sin(angle);
 110         bigger = fabs(dx);
 111         dist = fabs(dy);
 112         if (dist > bigger)
 113                 bigger = dist;
 114         dx /= bigger;
 115         dy /= bigger;
 116
 117         /* check for long range tractor beams */
 118         /****  TEMPORARY CODE == DEBUGGING  ****/
 119         evtime = Now.eventptr[E_LRTB]->date - Now.date;
 120 #ifdef xTRACE
 121         if (Trace)
 122                 printf("E.ep = %p, ->evcode = %d, ->date = %.2f, "
 123                        "evtime = %.2f\n",
 124                         Now.eventptr[E_LRTB], Now.eventptr[E_LRTB]->evcode,
 125                         Now.eventptr[E_LRTB]->date, evtime);
 126 #endif
 127         if (time > evtime && Etc.nkling < 3) {
 128                 /* then we got a LRTB */
 129                 evtime += 0.005;
 130                 time = evtime;
 131         } else
 132                 evtime = DBL_MIN;
 133         dist = time * speed;
 134
 135         /* move within quadrant */
 136         Sect[Ship.sectx][Ship.secty] = EMPTY;
 137         x = Ship.sectx + 0.5;
 138         y = Ship.secty + 0.5;
 139         xn = NSECTS * dist * bigger;
 140         n = xn + 0.5;
 141 #ifdef xTRACE
 142         if (Trace)
 143                 printf("dx = %.2f, dy = %.2f, xn = %.2f, n = %d\n",
 144                         dx, dy, xn, n);
 145 #endif
 146         Move.free = 0;
 147
 148         for (i = 0; i < n; i++) {
 149                 ix = (x += dx);
 150                 iy = (y += dy);
 151 #ifdef xTRACE
 152                 if (Trace)
 153                         printf("ix = %d, x = %.2f, iy = %d, y = %.2f\n",
 154                                 ix, x, iy, y);
 155 #endif
 156                 if (x < 0.0 || y < 0.0 || x >= sectsize || y >= sectsize) {
 157                         /* enter new quadrant */
 158                         dx = Ship.quadx * NSECTS + Ship.sectx + dx * xn;
 159                         dy = Ship.quady * NSECTS + Ship.secty + dy * xn;
 160                         if (dx < 0.0)
 161                                 ix = -1;
 162                         else
 163                                 ix = dx + 0.5;
 164                         if (dy < 0.0)
 165                                 iy = -1;
 166                         else
 167                                 iy = dy + 0.5;
 168 #ifdef xTRACE
 169                         if (Trace)
 170                                 printf("New quad: ix = %d, iy = %d\n", ix, iy);
 171 #endif
 172                         Ship.sectx = x;
 173                         Ship.secty = y;
 174                         compkldist(0);
 175                         Move.newquad = 2;
 176                         attack(0);
 177                         checkcond();
 178                         Ship.quadx = ix / NSECTS;
 179                         Ship.quady = iy / NSECTS;
 180                         Ship.sectx = ix % NSECTS;
 181                         Ship.secty = iy % NSECTS;
 182                         if (ix < 0 || Ship.quadx >= NQUADS || iy < 0 ||
 183                             Ship.quady >= NQUADS) {
 184                                 if (!damaged(COMPUTER)) {
 185                                         dumpme(0);
 186                                 } else
 187                                         lose(L_NEGENB);
 188                         }
 189                         initquad(0);
 190                         n = 0;
 191                         break;
 192                 }
 193                 if (Sect[ix][iy] != EMPTY) {
 194                         /* we just hit something */
 195                         if (!damaged(COMPUTER) && ramflag <= 0) {
 196                                 ix = x - dx;
 197                                 iy = y - dy;
 198                                 printf("Computer reports navigation error; "
 199                                        "%s stopped at %d,%d\n",
 200                                         Ship.shipname, ix, iy);
 201                                 Ship.energy -= Param.stopengy * speed;
 202                                 break;
 203                         }
 204                         /* test for a black hole */
 205                         if (Sect[ix][iy] == HOLE) {
 206                                 /* get dumped elsewhere in the galaxy */
 207                                 dumpme(1);
 208                                 initquad(0);
 209                                 n = 0;
 210                                 break;
 211                         }
 212                         ram(ix, iy);
 213                         break;
 214                 }
 215         }
 216         if (n > 0) {
 217                 dx = Ship.sectx - ix;
 218                 dy = Ship.secty - iy;
 219                 dist = sqrt(dx * dx + dy * dy) / NSECTS;
 220                 time = dist / speed;
 221                 if (evtime > time) {
 222                         /* spring the LRTB trap */
 223                         time = evtime;
 224                 }
 225                 Ship.sectx = ix;
 226                 Ship.secty = iy;
 227         }
 228         Sect[Ship.sectx][Ship.secty] = Ship.ship;
 229         compkldist(0);
 230         return (time);
 231 }