games/trek/move.c

   1 /*      @(#)move.c      8.1 (Berkeley) 5/31/93                  */
   2 /*      $NetBSD: move.c,v 1.11 2011/07/03 06:44:01 mrg Exp $    */
   3
   4 /*
   5  * Copyright (c) 1980, 1993
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include <stdio.h>
  34 #include <math.h>
  35 #include <float.h>
  36 #include "trek.h"
  37
  38 /*
  39 **  Move Under Warp or Impulse Power
  40 **
  41 **      `Ramflag' is set if we are to be allowed to ram stars,
  42 **      Klingons, etc.  This is passed from warp(), which gets it from
  43 **      either play() or ram().  Course is the course (0 -> 360) at
  44 **      which we want to move.  `Speed' is the speed we
  45 **      want to go, and `time' is the expected time.  It
  46 **      can get cut short if a long range tractor beam is to occur.  We
  47 **      cut short the move so that the user doesn't get docked time and
  48 **      energy for distance which he didn't travel.
  49 **
  50 **      We check the course through the current quadrant to see that he
  51 **      doesn't run into anything.  After that, though, space sort of
  52 **      bends around him.  Note that this puts us in the awkward posi-
  53 **      tion of being able to be dropped into a sector which is com-
  54 **      pletely surrounded by stars.  Oh Well.
  55 **
  56 **      If the SINS (Space Inertial Navigation System) is out, we ran-
  57 **      domize the course accordingly before ever starting to move.
  58 **      We will still move in a straight line.
  59 **
  60 **      Note that if your computer is out, you ram things anyway.  In
  61 **      other words, if your computer and sins are both out, you're in
  62 **      potentially very bad shape.
  63 **
  64 **      Klingons get a chance to zap you as you leave the quadrant.
  65 **      By the way, they also try to follow you (heh heh).
  66 **
  67 **      Return value is the actual amount of time used.
  68 **
  69 **
  70 **      Uses trace flag 4.
  71 */
  72
  73 double
  74 move(int ramflag, int course, double time, double speed)
  75 {
  76         double                  angle;
  77         double                  x, y, dx, dy;
  78         int             ix = 0, iy = 0;
  79         double                  bigger;
  80         int                     n;
  81         int             i;
  82         double                  dist;
  83         double                  sectsize;
  84         double                  xn;
  85         double                  evtime;
  86
  87 #ifdef xTRACE
  88         if (Trace)
  89                 printf("move: ramflag %d course %d time %.2f speed %.2f\n",
  90                         ramflag, course, time, speed);
  91 #endif
  92         sectsize = NSECTS;
  93         /* initialize delta factors for move */
  94         angle = course * 0.0174532925;
  95         if (damaged(SINS))
  96                 angle += Param.navigcrud[1] * (franf() - 0.5);
  97         else
  98                 if (Ship.sinsbad)
  99                         angle += Param.navigcrud[0] * (franf() - 0.5);
 100         dx = -cos(angle);
 101         dy = sin(angle);
 102         bigger = fabs(dx);
 103         dist = fabs(dy);
 104         if (dist > bigger)
 105                 bigger = dist;
 106         dx /= bigger;
 107         dy /= bigger;
 108
 109         /* check for long range tractor beams */
 110         /****  TEMPORARY CODE == DEBUGGING  ****/
 111         evtime = Now.eventptr[E_LRTB]->date - Now.date;
 112 #ifdef xTRACE
 113         if (Trace)
 114                 printf("E.ep = %p, ->evcode = %d, ->date = %.2f, "
 115                        "evtime = %.2f\n",
 116                         Now.eventptr[E_LRTB], Now.eventptr[E_LRTB]->evcode,
 117                         Now.eventptr[E_LRTB]->date, evtime);
 118 #endif
 119         if (time > evtime && Etc.nkling < 3) {
 120                 /* then we got a LRTB */
 121                 evtime += 0.005;
 122                 time = evtime;
 123         } else
 124                 evtime = DBL_MIN;
 125         dist = time * speed;
 126
 127         /* move within quadrant */
 128         Sect[Ship.sectx][Ship.secty] = EMPTY;
 129         x = Ship.sectx + 0.5;
 130         y = Ship.secty + 0.5;
 131         xn = NSECTS * dist * bigger;
 132         n = xn + 0.5;
 133 #ifdef xTRACE
 134         if (Trace)
 135                 printf("dx = %.2f, dy = %.2f, xn = %.2f, n = %d\n",
 136                         dx, dy, xn, n);
 137 #endif
 138         Move.free = 0;
 139
 140         for (i = 0; i < n; i++) {
 141                 ix = (x += dx);
 142                 iy = (y += dy);
 143 #ifdef xTRACE
 144                 if (Trace)
 145                         printf("ix = %d, x = %.2f, iy = %d, y = %.2f\n",
 146                                 ix, x, iy, y);
 147 #endif
 148                 if (x < 0.0 || y < 0.0 || x >= sectsize || y >= sectsize) {
 149                         /* enter new quadrant */
 150                         dx = Ship.quadx * NSECTS + Ship.sectx + dx * xn;
 151                         dy = Ship.quady * NSECTS + Ship.secty + dy * xn;
 152                         if (dx < 0.0)
 153                                 ix = -1;
 154                         else
 155                                 ix = dx + 0.5;
 156                         if (dy < 0.0)
 157                                 iy = -1;
 158                         else
 159                                 iy = dy + 0.5;
 160 #ifdef xTRACE
 161                         if (Trace)
 162                                 printf("New quad: ix = %d, iy = %d\n", ix, iy);
 163 #endif
 164                         Ship.sectx = x;
 165                         Ship.secty = y;
 166                         compkldist(0);
 167                         Move.newquad = 2;
 168                         attack(0);
 169                         checkcond();
 170                         Ship.quadx = ix / NSECTS;
 171                         Ship.quady = iy / NSECTS;
 172                         Ship.sectx = ix % NSECTS;
 173                         Ship.secty = iy % NSECTS;
 174                         if (ix < 0 || Ship.quadx >= NQUADS || iy < 0 ||
 175                             Ship.quady >= NQUADS) {
 176                                 if (!damaged(COMPUTER)) {
 177                                         dumpme(0);
 178                                 } else
 179                                         lose(L_NEGENB);
 180                         }
 181                         initquad(0);
 182                         n = 0;
 183                         break;
 184                 }
 185                 if (Sect[ix][iy] != EMPTY) {
 186                         /* we just hit something */
 187                         if (!damaged(COMPUTER) && ramflag <= 0) {
 188                                 ix = x - dx;
 189                                 iy = y - dy;
 190                                 printf("Computer reports navigation error; "
 191                                        "%s stopped at %d,%d\n",
 192                                         Ship.shipname, ix, iy);
 193                                 Ship.energy -= Param.stopengy * speed;
 194                                 break;
 195                         }
 196                         /* test for a black hole */
 197                         if (Sect[ix][iy] == HOLE) {
 198                                 /* get dumped elsewhere in the galaxy */
 199                                 dumpme(1);
 200                                 initquad(0);
 201                                 n = 0;
 202                                 break;
 203                         }
 204                         ram(ix, iy);
 205                         break;
 206                 }
 207         }
 208         if (n > 0) {
 209                 dx = Ship.sectx - ix;
 210                 dy = Ship.secty - iy;
 211                 dist = sqrt(dx * dx + dy * dy) / NSECTS;
 212                 time = dist / speed;
 213                 if (evtime > time) {
 214                         /* spring the LRTB trap */
 215                         time = evtime;
 216                 }
 217                 Ship.sectx = ix;
 218                 Ship.secty = iy;
 219         }
 220         Sect[Ship.sectx][Ship.secty] = Ship.ship;
 221         compkldist(0);
 222         return (time);
 223 }