games/trek/move.c

   1 /*
   2  * Copyright (c) 1980, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * @(#)move.c   8.1 (Berkeley) 5/31/93
  34  * $FreeBSD: src/games/trek/move.c,v 1.6 1999/11/30 03:49:50 billf Exp $
  35  * $DragonFly: src/games/trek/move.c,v 1.3 2006/09/07 21:19:44 pavalos Exp $
  36  */
  37
  38 # include       "trek.h"
  39
  40 /*
  41 **  Move Under Warp or Impulse Power
  42 **
  43 **      `Ramflag' is set if we are to be allowed to ram stars,
  44 **      Klingons, etc.  This is passed from warp(), which gets it from
  45 **      either play() or ram().  Course is the course (0 -> 360) at
  46 **      which we want to move.  `Speed' is the speed we
  47 **      want to go, and `p_time' is the expected time.  It
  48 **      can get cut short if a long range tractor beam is to occur.  We
  49 **      cut short the move so that the user doesn't get docked time and
  50 **      energy for distance which he didn't travel.
  51 **
  52 **      We check the course through the current quadrant to see that he
  53 **      doesn't run into anything.  After that, though, space sort of
  54 **      bends around him.  Note that this puts us in the awkward posi-
  55 **      tion of being able to be dropped into a sector which is com-
  56 **      pletely surrounded by stars.  Oh Well.
  57 **
  58 **      If the SINS (Space Inertial Navigation System) is out, we ran-
  59 **      domize the course accordingly before ever starting to move.
  60 **      We will still move in a straight line.
  61 **
  62 **      Note that if your computer is out, you ram things anyway.  In
  63 **      other words, if your computer and sins are both out, you're in
  64 **      potentially very bad shape.
  65 **
  66 **      Klingons get a chance to zap you as you leave the quadrant.
  67 **      By the way, they also try to follow you (heh heh).
  68 **
  69 **      Return value is the actual amount of time used.
  70 **
  71 **
  72 **      Uses trace flag 4.
  73 */
  74
  75 double
  76 move(int ramflag, int course, double p_time, double speed)
  77 {
  78         double                  angle;
  79         double                  x, y, dx, dy;
  80         int             ix, iy;
  81         double                  bigger;
  82         int                     n;
  83         int             i;
  84         double                  dist;
  85         double                  sectsize;
  86         double                  xn;
  87         double                  evtime;
  88
  89         ix = iy = 0;
  90 #       ifdef xTRACE
  91         if (Trace)
  92                 printf("move: ramflag %d course %d time %.2f speed %.2f\n",
  93                         ramflag, course, p_time, speed);
  94 #       endif
  95         sectsize = NSECTS;
  96         /* initialize delta factors for move */
  97         angle = course * 0.0174532925;
  98         if (damaged(SINS))
  99                 angle += Param.navigcrud[1] * (franf() - 0.5);
 100         else
 101                 if (Ship.sinsbad)
 102                         angle += Param.navigcrud[0] * (franf() - 0.5);
 103         dx = -cos(angle);
 104         dy = sin(angle);
 105         bigger = fabs(dx);
 106         dist = fabs(dy);
 107         if (dist > bigger)
 108                 bigger = dist;
 109         dx /= bigger;
 110         dy /= bigger;
 111
 112         /* check for long range tractor beams */
 113         /****  TEMPORARY CODE == DEBUGGING  ****/
 114         evtime = Now.eventptr[E_LRTB]->date - Now.date;
 115 #       ifdef xTRACE
 116         if (Trace)
 117                 printf("E.ep = %p, ->evcode = %d, ->date = %.2f, evtime = %.2f\n",
 118                         (void *)Now.eventptr[E_LRTB],
 119                         Now.eventptr[E_LRTB]->evcode,
 120                         Now.eventptr[E_LRTB]->date, evtime);
 121 #       endif
 122         if (p_time > evtime && Etc.nkling < 3)
 123         {
 124                 /* then we got a LRTB */
 125                 evtime += 0.005;
 126                 p_time = evtime;
 127         }
 128         else
 129                 evtime = -1.0e50;
 130         dist = p_time * speed;
 131
 132         /* move within quadrant */
 133         Sect[Ship.sectx][Ship.secty] = EMPTY;
 134         x = Ship.sectx + 0.5;
 135         y = Ship.secty + 0.5;
 136         xn = NSECTS * dist * bigger;
 137         n = xn + 0.5;
 138 #       ifdef xTRACE
 139         if (Trace)
 140                 printf("dx = %.2f, dy = %.2f, xn = %.2f, n = %d\n", dx, dy, xn, n);
 141 #       endif
 142         Move.free = 0;
 143
 144         for (i = 0; i < n; i++)
 145         {
 146                 ix = (x += dx);
 147                 iy = (y += dy);
 148 #               ifdef xTRACE
 149                 if (Trace)
 150                         printf("ix = %d, x = %.2f, iy = %d, y = %.2f\n", ix, x, iy, y);
 151 #               endif
 152                 if (x < 0.0 || y < 0.0 || x >= sectsize || y >= sectsize)
 153                 {
 154                         /* enter new quadrant */
 155                         dx = Ship.quadx * NSECTS + Ship.sectx + dx * xn;
 156                         dy = Ship.quady * NSECTS + Ship.secty + dy * xn;
 157                         if (dx < 0.0)
 158                                 ix = -1;
 159                         else
 160                                 ix = dx + 0.5;
 161                         if (dy < 0.0)
 162                                 iy = -1;
 163                         else
 164                                 iy = dy + 0.5;
 165 #                       ifdef xTRACE
 166                         if (Trace)
 167                                 printf("New quad: ix = %d, iy = %d\n", ix, iy);
 168 #                       endif
 169                         Ship.sectx = x;
 170                         Ship.secty = y;
 171                         compkldist(0);
 172                         Move.newquad = 2;
 173                         attack(0);
 174                         checkcond();
 175                         Ship.quadx = ix / NSECTS;
 176                         Ship.quady = iy / NSECTS;
 177                         Ship.sectx = ix % NSECTS;
 178                         Ship.secty = iy % NSECTS;
 179                         if (ix < 0 || Ship.quadx >= NQUADS || iy < 0 || Ship.quady >= NQUADS)
 180                         {
 181                                 if (!damaged(COMPUTER))
 182                                 {
 183                                         dumpme(0);
 184                                 }
 185                                 else
 186                                         lose(L_NEGENB);
 187                         }
 188                         initquad(0);
 189                         n = 0;
 190                         break;
 191                 }
 192                 if (Sect[ix][iy] != EMPTY)
 193                 {
 194                         /* we just hit something */
 195                         if (!damaged(COMPUTER) && ramflag <= 0)
 196                         {
 197                                 ix = x - dx;
 198                                 iy = y - dy;
 199                                 printf("Computer reports navigation error; %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                         {
 207                                 /* get dumped elsewhere in the galaxy */
 208                                 dumpme(1);
 209                                 initquad(0);
 210                                 n = 0;
 211                                 break;
 212                         }
 213                         ram(ix, iy);
 214                         break;
 215                 }
 216         }
 217         if (n > 0)
 218         {
 219                 dx = Ship.sectx - ix;
 220                 dy = Ship.secty - iy;
 221                 dist = sqrt(dx * dx + dy * dy) / NSECTS;
 222                 p_time = dist / speed;
 223                 if (evtime > p_time)
 224                         p_time = evtime;                /* spring the LRTB trap */
 225                 Ship.sectx = ix;
 226                 Ship.secty = iy;
 227         }
 228         Sect[Ship.sectx][Ship.secty] = Ship.ship;
 229         compkldist(0);
 230         return (p_time);
 231 }